I wean them. Just a little of pellets mixed in at first, then add a little bit more every feeder fill time. (One scoop to first feeder time, then two, then three, until they're completely switched.)
No. You can, but shouldn't. I've fed layer pellets to rooster before, and they were fine. The protein is more important. Whenever my birds didn't have the layer pellets early, I had problems, and some wasn't to be fixed...
Possibly.
Cannibalism doesn't care about space.... What started it is the question. I'd question the feed first. Go up to the highest protein level grain as possible. I'd have them on layer pellets by now, though some wouldn't agree.
No, that's where he's been plucked. I'm saying do a mite check because that can sometimes be a reason for balding, though I doubt that's the case. I'm thinking flock mates plucked him.
Too young to molt. He's getting plucked, possible attacked. I'm thinking more plucked. Check out other birds in the flock as well. Also check for mites.