Wow. I can't believe someone is making an AVP mod. If it wasn't such trouble to reinstall the RA2 modding tools, I'd give you a hand.
BTW, the assault rifle you were talking about earlier is the M41A Pulse Rifle (just to show off my trivial knowledge of the AvP universe

)
BTW, I hope you include all the species real strengths and weaknesses.
USCM: So much firepower. Anything that tries head on attacks gets ripped apart. And they outrange everything. However, not very maneuverable, and no defensive mechanism (ala leaping away, cloaking)
Preds: Cloaking, powerful close range attacks, limited long range attacks, not incredibly fast.
Aliens: Fast, one or two hit kills up close, but no long range attacks. Can reproduce rapidly.
Part of me thinks this would be better as a Generals mod, the engine has more possibilities, although making infantry is a pain. Anyway, good luck!