I would leave them be to work it out.
As long as there's no copious blood drawn and/or new bird is not trapped/pinned down and beaten unmercilessly, let them work it out. Every time you interfere or remove new birds, they'll have to start the pecking order thing all over again.
Is the BR the...
Not sure, it could.... chickens don't like change.
If I was going to keep more than one breed for hatching pure breeds,
I'd keep the cock/erels and their pullets/hens separate full time right from the get go.
I would separate your bully hen for at least a week.
Then toss her back in and see what happens.
Or if you're not incredibly fond of her....soup.
Multiple males can work....or not.
Be ready to separate if need be,
sounds like the bully jail situation should be resolved before the cockerel start...