You can make a roblox fps game by simply use FE Gun Kit Viewmodel. Or they also uses normal arms too, There's no difference. You could make a R15 or R6 Fps game with FE Gun kit. No problem about rigging or stuff but i suggests you to use R6, Next you could add Main Menu Screens or stuff. And also Team combat is fine too, FE gun kit doesn't damage your teammates.
No problem, Check out my channel Called Al or jsut search "Al roblox" on yt. I also did some fe gun kit showcase vids on that channel