Hey machinimagames,
I can help with a few of these. Yes you can add camo to weapons. Here is a thread which has some for sale. http://forum.thegamecreators.com/?m=forum_view&t=173249&b=24
As of right now there is no way tohave weapon unlocks or anything similar in the multiplayer as the multiplayer in FPSC is very limited. For the other MP question, Im not too sure if that is possible, as the weapons are built with the game when u build the game. Maybe there is way to do a "patch" but I am not sure.
For friendlt AI, if you have v1.17 or higher, go into your scriptbank,and there should be a folder named "DAI" or "Dark AI" Assign a character "DAI_AppearAlly" for his appear script, and "DAI_Main" for his main script.
Yes you can have choppers and tanks, there are a few examples on the forums of people using them. In the Game Creator Store there is an animated chopper for sale.
I recently learned to sleep with my eyes open. ..... God am I tired