[Not on Steam. any particular reason?]

Theater of war is developed by 1C. Battlefront just published it for 1C in the west while 1C holds all rights for the title, and decides freely on which platform to distribute it.  Combat mission is developed and self published by Battlefront, and they don't see steam as a fitting distribution platform for them.

[Windows 10 - CM Compatibility?]

I've upgraded from windows 8.1 to windows 10, while adding more ram and replacing the gpu.    All of my CM titles work fine and required no re licence whatsoever.