The reason the minifig doesn't render in 1st person is because if it did, you would be able to see your visor and helmet if you had one, and i think this would be annoying.
What? I've seen my hand while swinging before... But I don't really look...
i have an idea, why dont you model the hand ON the gun so when you look at it, it looks like your hand? and when you reload with some specail weapons, your hand comes over and dances a jig or something?
I turned on the player rendering once, but you couldn't seen when you looked down, because your avatar was in the way.