1) yes it is copyrighted, 100%. BUT you never told us if you plan to make your game commercial...
because if not its a freeware game, and thus you are allowed to use anything from predator franchise.

Like me, im making a Survival Horror game ala Resident Evil, so if i not go commercial i could call my game, i.e. "Resident Evil: The Lost Chapter" or anything. But i do not so, because i dont know yet if i ever wanna sell it or not.

But please anyone correct me if im wrong.