One thing I would look out for in their temporary accommodation is that the larger rats don't bully the smaller ones, wth regards to food and space.

I think in general male rats, from what I've seen, tend to get on better with each other than female rats do! When they're in their new, more spacious cages, I wouldn't worry too much about them fighting. Yes, it's a possibility, but a relatively unlikely one at that, and neutering them, whilst lessening the chance further, does stress both them and your pocket! Of course if you plan on keeping a female with them then I'm sure you would know to get the males neutered, probably even with an older female, as the male could make her life a misery trying to mate with her.

They are all lovely - congratulations on your new additions!