@The_CaptI took your advice and tried mission 5 again. By dispersing infantry throughout the woods I was able to figure out where the Soviets were and then hit them while they were moving, which seems like the safest way to fight.
After preserving my forces well enough I ran the team into the ground on the next mission, and it looks like only barely scraped by getting on to mission 7. It was really interesting getting the behind the scenes context for mission 5, do you have any similar observations for mission 6? I ask because the expectations I had from the briefing and what I ended up noticing about the fight were a little different from each other, which I'm sure was intentional. I struggled to make decisions based on the one hour time limit, size, and force composition. Attacking positions yielded information, but was costly. Looking at the remaining enemy after the fight ended I have to admit I have no idea how I'd clear them all out. Were beta testers able to take and hold all objectives?