Integrating Our Motley Flock - Help!

Hi, I'm brand new here, and pretty new to raising chickens.

We started out with 3 pullets from a local farm that we were told were 4-5 months old and would lay any day - that day has still not come. They are a bossy, mean-ish BO, a really sweet BR, and a Black Australorp we call Voldemort who I can't stand. They live together in a small backyard coop with attached run that is tractor-style. We've had them for 6 weeks.

We ordered some rare breeds and a couple Polish from mypetchicken. While we were waiting for them to arrive, my wife bought 5 "rainbow layers" day old from our feed store.

So now, we have in two separate brooders: the 5 EE who are close to 6 weeks old now, 7 various chicks who will be 2 weeks old tomorrow - one of them, a feather-legged, is literally the tiniest chick you can imagine. We think she might be a Mille Fleur? The others are 2 polish, 2 maybe EE, one maybe Wyandotte, one I have no clue.

We are having a very large coop built to our specifications and the guy is actually a little ahead of schedule, it should be finished and delivered within the next week or so, two weeks tops. How do we do this? Do we wait until the tiniest chicks are big and feathered enough and then throw all 3 groups into the new coop at the same time? The mean BO, Irene, tried to eat the face off one of the now 6 weekers a couple of weeks ago when I had her on the porch where their brooder is giving her some minor first aid.

Are we doomed to have chickens fighting to the death?

We welcome suggestions as we plan and stress out about what we've gotten ourselves into.