If this boy is injuring your other rats because of aggression issues then he needs a neuter. How old is he?
Also do not put Sugar in the cage with him even for cage cleaning since this is how you get babies and with their history (bleeding issue for Sugar and aggression and possible genetic obesity for BB) you could be getting some awfully unhealthy babies. Just remember it can take only a few seconds and you cannot stop a mating if its gonna happen.
Neutering him may minimize the food aggression. And if there wasn't any food involved in Powder's instance it's not that ('course, he may have injured her attempted to mate with her... watch your femmes for pregnancy...)
There's no domestic rat that could weigh anywhere near 25 lbs. I think Zucker rats (genetic obesity gene) weigh like 4 lbs or something like that at the top end, and they cannot move or groom or anything