Hi Esmaralder and welcome to the forum.
Have you tried waiting until all the hens have settled down (around 8.15 to give them a chance to get nice and sleepy) then wiping vinegar over the wings of the dominant hens in their coop, then doing the same with the newbies, and transferring them to the coop with the bossy ones in? Shut the pophole, and get down there as early as you can manage, to let them out and see what happens. This has worked for me - the idea is that they all sleep together, all wake up smelling the same (!) and go out as a flock to eat breakfast. Then remove the second coop, so the next night they have no option but to go in with the bossy ones. The bossy ones will go to roost first, so if you go down after they've settled, when the newbies are really wanting somewhere to roost, you can then encourage them to take those important steps up into the scary dark house for themselves, rather than you lifting them in. I've found it helps to make a little enclosure with a length of wire netting or similar, round the entrance to the pophole, with the new hens inside, and then gently push them towards the pophole with this as support. Then when they're inside, shut the pophole. There will be some bumbling around, but in the dark they won't be attacked and will settle down after a few minutes. You may need to encourage them to go in for a couple more nights until they get the idea and have established their own places to sleep on the perches. Don't try this too early, or they'll just come out again. After a night or two, you'll go down there and find everyone is all nicely tucked up in bed and then there'll be no more problems. As you say they are foraging together with no problems, I don't think it will take long for them to roost together if you help them to do this in the way I've suggested. Just a thought - you are sure the coop is clean of redmite? as this may be the reason the new ones don't like going in it.
By all means get a cockerel if you really want one, and have tolerant neighbours, but this isn't certain to solve the present problem, and may introduce new difficulties in itself, so I'd sort out the roosting and check the redmite first.
