AFAIK, the wave's would just look wierd, since there's a wave animation for the flags but they can be there. Also, I believe yes, American Flag background should be no problem.
Back when electricity, probe bodies, and docking were all mod based, there was a plugin for Dynasat that kept your "top" pointed towards whatever body you were orbiting. But that was long ago, far away. Better days then. The only solar panels to be found were dynasat, and CardboardboxProcessor's KOCMOC mods, Mechanical Mouse's Kethane was all the rage, it used electricity, and his satellite pack had the first Ion engines. Good days. Good days.
U.K.K United Kerbal Kommunes No need for the Hammer and Sickle, but if you feel like it, a different symbol in the middle would be cool. And I would think replacing the Red color scheme with a green one would be cool.
I've put a X200-32 with ASAS, large RCS tank, large probe body, and docked it to a crew tank, ASAS, Large RCS tank, large probe body, X200-8, and Skipper, with no wobble at all. TBH, this probably replaced the CBM mod for me.