Howler

Do you have ReShade installed? This can cause uncontrollable spinning. If you do then try Alt-E, might stop it. Even if you don’t have ReShade this might help.

In Iron C2 is displayed differently depending on the turn phase you are in.  There is the Orders Phase and the Action/Playback Phase. 
Skill level Iron gives a more detailed portrayal of a units C2 status during the action/playback phase in WEGO.
The difference between Elite and Iron is when you are in action/playback phase and you have a friendly unit selected.  In this situation you can only see what the selected friendly unit is aware of to include other friendly units.  This aids in the understanding of C2 and how C2, or the lack of it, plays a role in how this unit may react to different situations.  When you unselect the unit all your units are again displayed along with what information you have on OpFor units.  When you are in orders phase and you select a friendly unit all other friendly units remained displayed, just like in Elite. 
See below for a more detailed discussion. 
 
 
 

Wasn't CAS enhanced in this title also?
And, tank riders FTW!!!

With 1-10k in ammo, no vehicle of mine travels anywhere without first firing a few rounds at every terrain feature or structure on it's path. I don't need contact markers and I'm sure you can find others like me who spend a lot of ammo firing at nothing!
It's worthwhile for the times you discover that you aren't firing at nothing.
It's not gamey and part of SOP by more players than just little old me... just saying.
Feel free to be smug when such fire is harmless to your position but don't then shed tears when it isn't.

The "?" symbols are very inaccurate without solid spotting.  It is anything but gamey to shoot at them.

I originally bought the Paradox boxed version of SF1. I sent helpdesk my info and they issued me a new base game key so I could purchase the upgrade.

I notice you are playing CMSF2 from the blue force side so I'd imagine the professional soldiers with high experience is partly causing this. Switch to WW2 titles or to the Syrians and you may experience something a touch different. It's also easier to spot things that are moving so the Syrians maybe spotting your troops as they move into position. You also become very easy to spot once your pixeltruppen start firing their weapons effectively sending giant "I am here" flares.
Yes the recent patch did toughen up the morale of infantry in hard cover but that was after some horrible (IMO and I think many others) experiences of troops breaking far to easily and fleeing hard cover/good positions where running meant getting killed quicker. See my German "Fire and Rubble" Beta AAR thread over in the CMRT forum where I explain my experiences in more detail fighting in an urban environment.
Tips and tricks:
- High explosive is now incredibly important in dislodging an enemy from building (or at least doing it quicker).
- Watch you ammo counts. Your troops will be expending a terrible lot of ammunition now in city fighting given the morale tweaks.
- Keep in mind the calibre of your small arms. A .50 cal round can punch right through a building and out the other side. A 5.56 NATO probably doesn't get past the wall.
- Earlier comments are right. If you target the enemy infantry directly your troops will only shoot when they have positive spots. Plot an area fire order and the troops will keep up the fire. Just because they will likely lose sight of the enemy in the occupied building doesn't mean they can't cause the enemy casualties if the enemy is still occupying the location the fire is heading towards.
- If possible try to get into position first so your troops have more chance of spotting and shooting first.
- The first few seconds of the engagement are critical. Try to overwhelm the enemy in the first few seconds of a firefight when they are unaware and still out of position/exposed in windows etc. Open fire with one team of a few rifles it alerts the enemy. Open with a whole platoon and there's a good 10 fold increase of bullets heading their way as they are exposed. My AAR has a good example of this where the Soviet slaughtered pretty much a full platoon and about 15 seconds as they were still setting up inside the building.
- The hunt command is essential for entering pretty much any building in a modern title so your troops are guns up and ready to engage contact.
 
Hope that helps.

It sounds like it is probably working as intended.  If you are allowing your troops to "fire at will" or you are giving them a Target command (red line) on the OpFor teams what you are describing will happen.  For the reasons explained above.  Constant Area Fire is needed to suppress and maintain suppression.  I often Target the action spot in front of the building or target the building.  Don't target the OpFor teams (in this particular situation).
Yes there are two general choices.  The first is lead broom from a distance until the building is brought down or the OpFor displace or die in place.  The second choice (when you don't have the ability for #1) is heavy suppression and close & hose.  Both options need constant Area Fire and will use up lots of ammo.  
Nine turns is a long time to us players.  In pixeltroopen game time that is only nine minutes.  So it sounds like nine minutes of sporadic fire has been used.  Five minutes of constant fire with enough weapons will generally get the desired result.     

In short, it is working as intended now. The TacAI used to be very prone to fleeing, even out of good cover. The player could essentially shoot the enemy off their position, which is not realistic at all. 
Your two bullet points are correct. The only way to dislodge a determined enemy from a building is to either manually clear the building (costly, time consuming, dangerous, hard, etc...) or to level the building and kill the survivors. Urban warfare is extremely tough, extremely deadly, and there is no easy way of doing it. 
Its also realistic for the enemy to be so survivable in urban environments despite your veteran marines with scoped rifles. Hitting anything in an urban environment is extremely difficult, despite the closer ranges. More cover and concealment, harder to spot man sized targets despite generally being closer, better and more plentiful cover... the list goes on. Again, the short of it is that urban warfare is really hard, for anyone. Doesn't matter how well you are trained or how sexy your equipment is, urban warfare is a great equalizer. 

The trick is that you don't need to actually enter the occupied house. Just get your guys close enough that they will spot and shoot the enemies inside.

That does sound frustrating.  The below might be what is happening and how to get at the OpFor. 
Area fire is needed for suppression.  If you Target an OpFor team, they'll duck. Then, with them out of LOS, your men will stop shooting, their morale will recover, they will pop up and shoot your guys, in turn your guys will shoot at them, they'll duck, recover, repeat.  Area target will keep the incoming fire at their location even when they are out of LOS.  This also gives you the option to move another team into grenade range while the OpFor team is suppressed.  
Also It takes approximately 30 seconds for a Pinned unit to recover once fire stops being directed at them. 
And Hand grenade range is 3 Action Spots but only 1 A/S for buildings (must be next to the building).
 

The cover effect of buildings depends a lot on the distance, as well as the type of building etc. I don't think they are too strong. And I don't think they got stronger in the recent patch. It's just that troops won't readily run out of the building to get shot outside anymore. An improvement, I think.
Instead of playing whack-a-mole, try suppressing them with one team, while you move another team closer.

First I want to say, that I have no problem to wait. I have enough other games to play and even in the combat mission games, which I own, is enough content for me to play for years.
 
Then I will explain, why I didin't took it too serious (and like always I hope it will be understandable, because my english is reaaaaly bad😉)

First I think that Steve said (in a interview?) that the module will be released this year.

And then I had the impression that Elvis was a little nerved about the permanent questions about a release date. So he gave the people a date. For his peace.
Additional he said that we should come back at the 7sth january and when it is not out then we will see then.
(15th post Page 24 this thread, I don't know how to quote different posts)
 
And I thought, that there would be an official release (real) date, it would not be buried in this thread.
These were my thoughts.

So I will be happy when it comes earlier, but I have no problem, when it comes at the 8th or when it comes later!

Understandable?

Greetings, Alex
 

The scenario we've been discussing actually starts cool, but thermals are generally less efficient in daytime desert conditions.  That doesn't necessarily mean worse than day optics / NVGs and it depends on multiple factors.
I'll repeat that individual anecdotes are almost entirely worthless for discussion of spotting in CM.  There are abstractions and spotting cycles for individual units that can lead to oddities like above, but they are unlikely to persist for long or be consistently repeatable.

https://combatmission.fandom.com/wiki/What_the_Germans_say
 

This is my experience also.  If not through the bocage they could throw over the bocage like they do with tall walls.
Below, in italics, is a post by @RockinHarry that describes throwing grenades over a tall wall.  I paraphrased the post.  
You can get frags thrown over a high wall by simple use of short range (~10m) area fire beyond a wall. You´ll either receive a blue or grey targeting line, indicating that as long as a unit has a weapon able to reach over a wall (grenades!) it will use them, although the unit can´t actually see the area beyond a wall. The targeting unit’s soldiers attempt to area fire with rifles and such, but can´t. The game mechanic cycles through available weapons until a grenade is selected and then thrown. That means you need to wait until the game picks a random grenade throw from the area target cycle.
Below is the drill for "Fire in the Hole" (grenades over a tall wall).    
1. Quick a team, with hand grenades, to an A/S along the wall opposite the OpFor.
2. Highlight waypoint & give team a Target order over the wall.
Notes: The AI will sometimes allow you to Target over the wall from 3 A/S (hand grenade range).  The most reliable location is next to the wall.  Smoke grenades can also be thrown over a wall.

Below, in italics, is a post by @YankeeDog that I have always found useful. 
Infantry will not attempt to close assault vehicles from inside a building; you have to order them outside. Also, NEVER give infantry a TARGET order if you want them to close assault a vehicle or bunker. The TARGET order tells a unit to use whatever weapons it has against the target, regardless of effectiveness. This can be useful, e.g., when you want a unit to shoot small arms at a tank from one direction to distract it, while another unit assaults the tank from a different direction. But the close assaulting unit should be left to make its own targeting decisions. Possibly a short cover arc to prevent it from engaging other, more distant enemy, but nothing more than this. Generally speaking, as long as an infantry unit is in good order and has hand grenades, it will use them on any armor or bunker that is in grenade range.
Rule of thumb; a fire team must be outside a building to close assault.  However grenades and demo charges will get thrown from the upper floors on to open topped vehicles.  
Below is my Grenade CQB vs Armor: 
1. Use a fire team with a lot of hand grenades (typically an assault team).  The fewer grenades the AI has it seems more reluctant to use them.  
2. Give fire team a 360oTarget Arc1 of 24 meters.
3. Exit building.  (teams must be outside to close assault vehicle) 
4. Fast fire team to within 2 A/S of the flank or rear of the tank.
5. On their own the team will throw grenades.
6. Prepare for the tank crew to dismount shooting.  (When they bail it will be like the OK Corral )  
Notes: 1) An Armor Target Arc will not allow the fire team to fire on the bailed out tank crew.

You can Acquire ammo and/or Share ammo. 
To Acquire ammo a team needs to be in a vehicle with ammo or in the same action spot of an ammo dump.  Acquire  allows for the taking of thousands of rounds and AT weapons.  The vehicle does not have to be in the same platoon as the Acquiring fire team.  
Ammo sharing distance is two action spots (about 16 meters).  Ammo sharing only takes place within an organizational unit (whatever highlights when you click that unit is a more practical definition).  Basically ammo sharing is within the same platoon and within 16 meters.   Sharing is done in small amounts, about a magazine at a time as @Erwin said.   
Probably the easiest way to observe ammo sharing is to move a mortar ammo bearer team (with mortar rounds) to within 16 meters of the mortar.  Then move the ammo bearers away.  In the user interface for the mortar you will see the number of mortar rounds available to the mortar team increase and decrease as the ammo bearers move in and out of ammo sharing range. 
In some cases a vehicle parked next to a building can share ammo with a fire team inside the building.  For the fire team to Acquire ammo from that same vehicle they would need to enter the vehicle. 

Exactly, I need to get reacquainted with CMBN as the last time BFC "improved" unit behavior - I needed to play SF/SF2/BS and avoided BN for near three years...
It's been good to see units surrender and not run back and forth in disarray towards known enemy positions.
Allow me to enjoy this before we break something else... is all I'm saying. No offense intended.

Speaking as a former mech soldier, there is one FO per platoon plus a FIST team at company level. The platoon FOs are usually SPCs, and the Company FIST team comprises a LT, a SSG and a PFC/SPC RTO, who ride in a M7 Bradley FIST/V.

In the US Army Forward Observers used to be embedded with an infantry company, and would usually be with the Company Commander to provide fire support calls. That's how things were in WW2, and in Korea and Vietnam. Post Vietnam (mid-70s-ish) the FIST came about. FIST stands for Fire Support Team. The idea was to provide FOs down to platoon level. In the 82d, a FIST would have a 2LT (FIST Chief), SSG (FIST Sergeant), and SP4/PFC RTO (all 3 with radios) as its HQ unit and they would be with the infantry Company HQ. By TOE an E5 SGT + PFC (RTO) would be with each infantry PLT leader. The FIST provides a more responsive fire support element. (We never had the 3 RTOs that were suppose to go to the platoons and most of our E5 FOs were E4s). 
In a mech unit it's a bit different. They have their own vehicle, and could detach one of the personnel down to platoon level, but the FIST vehicle allows them to be mobile so that's not as necessary (and doesn't work with armor unless they want to ride on top 🙂  The FIST vehicle provides all the radio nets they need to monitor and use, plus a laser target designator. Having an FO down to platoon level in a mech unit would be most useful if they were dismounted, I would think, and not so much when mounted.
Artillery battalions also deploy Fire Support Officers, who are usually CPTs or senior 1LTs (and they come with a SSG/SFC and a PFC) to infantry brigade HQs as a Fire Support Team to do fire support planning with the infantry brigade (now Brigade Combat Teams but in SF2 days a brigade). 
Back in WW2 you'd just get a 2LT Forward Observer, usually down to company level. But in general, things were more compact then. In a modern battlefield platoons tend to be spread more than they were in WW2, and the FIST is a way to have the artillery be more responsive.
Hope that helps.

Dave   (ex US Army, FIST Chief, Battery Fire Direction Officer, Brigade Fire Support Officer, FA Bn Asst S-3, FA Bn Fire Direction Officer).  All Airborne so my knowledge of the mech units is a little less detailed.

You need LOS to detonate the IED regardless of type.  You also need LOS for activation of Radio IEDs.
The triggerman needs LOS and has to be within proper range of the device (the three device types have different ranges).  The triggerman can't be "panicked".  If the triggerman is suppressed to the extent that his LOS, to the device, is broken (fetal position behind a low wall) he will not be able to detonate.  
If the triggerman cannot activate the IED the Target command won't be available.  If the IED is a dud then instead of showing Medium Radio IED (Activated) it will show Medium Radio IED (Malfunction).
An IED can be activated and detonated by any triggerman.  Example: A Wire triggerman can activate and/or detonate a cell or radio IED.
Some vehicles carry radio/cell IED jammers so you can't send a signal to your bomb to explode as it passes. Only wire IEDs work on those vehicles.  Bradleys & Strykers don’t have ECM jammers.  Some UK vehicles have the ECM jammer (don't remember which ones).
And just because I have these screenshots in my Imgur account.    Small, medium, large & huge.  Wire, cell or radio.  

 
And don't forget VBIEDs

Thing is no one needs to buy that concept as that's not how it works in CM. But somehow you seem to keep thinking it does even after AKD explained how it does works.
There are some quirks sometimes with sharing and Syrians have some limited capabilities IIRC, but for me too it does work in all CMx2 games.

None of those other units have thermal weapon sights.  They all have NVGs.
Read my post above again regarding information sharing.
 
It has a thermal weapon sight for the M249.
Yes, it has a much more powerful thermal imager than the weapon sights carried in the rifle squad.
The squad as a whole will be better because it is observing with 3x thermal sights instead of just one.
I think your conceptual problem here is that the thermal weapon sights are tied to the individual weapons and are not shown in the special equipment panel, whereas NVGs (light intensification, not thermal) are shown.  That's why I said the issue was obscure, because it is not readily apparent and takes careful testing to understand.  Possibly we could address this via a mod by denoting the thermal capability on the weapon icon itself?
 

First, the misunderstandings about how spotting works:
When a unit shares a positive contact, it generates a possible contact marker for units in C2 or proximity (including tanks) following a variable amount of time, regardless of whether or not the receiving unit has any chance of spotting the target itself (i.e. a unit in comms / proximity but with LoS completely blocked will still gain the possible contact marker).  If the unit has LoS to the location and has the means to see the given contact under the current conditions, this possible contact marker will increase the chances of the receiving unit gaining a positive contact for itself.  But this is most important: the unit must still spot the contact itself with its own sensors. All spotting has a highly variable "human factor" applied that can lead to significantly different outcomes in the same circumstances.  Anecdotes comparing times to spot are useless for drawing comparative conclusions about spotting beyond possible / not possible.  I don't care if 3 times in a row X spotted Z one minute sooner than Y, that does not mean X is better at spotting Z than Y.  Now repeat this 100 times carefully controlling all other factors and perhaps we can talk about quantitative differences in spotting ability. (Does this suck? Why yes, from experience it really does.) Second, what Erwin is encountering in George's scenario:
The US Mech Inf squad has access to 3x thermal small arms sights: 1 on each M249 and 1 on the Marksman's rifle.  A split off scout team from a full squad includes one M249 gunner, so it too has a thermal optic.  Here is what's a bit weird: the model switch showing these actually on the weapons is tied to a hard day / night time that does not vary based on conditions, but the thermal optics are still considered to be in use when they provide an advantage over day optics.  In this case, they seem to be allowing units with thermal optics to see further into the morning haze. Of the infantry units discussed in the scenario, only units with Javelin CLUs also have access to thermal optics. The units without thermals lose LoS at 1668m (at scenario start on my test map using the same date, time and conditions as George MC's map), so if a unit with thermals has shared a possible contact beyond this range with a unit without thermals, it will remain a possible contact for the receiving unit with no chance of becoming a positive contact unless conditions change or the unit alters its spotting equation (moves, acquires a new sensor).