It could take a lot longer, depending on the personality of your birds. We've always added in new chicks to the flock every other year, and I don't remember how long it used to take before we had the rooster, but when I introduced Penguin (who was by herself) the rooster wouldn't accept her until she starting laying, which unfortunately wasn't until she was almost 10 months old. The last three I added, I left them in their own pen for about two months, if I recall correctly, but I was probably too paranoid about it. I've never had a bantie so I don't know if the roos are nicer; I would at least keep the pullets separate until they're almost the same size as him (or the EE hen, if she's mean). If worse comes to worst, you can always lock up the offenders in cages instead of the pullets, so they have a chance to learn their way around the coop.
My set-up is a frame that fits under my nestboxes, covered with chicken wire, that I keep them in; and during the day I put them in a tractor beside the chicken run, so they'll be forced to look at each other.
For feed, you don't want to give the pullets layer feed until they are laying, because the calcium will stunt their growth. But if you have leftover mash at that point, the grownup hens will love to help them finish it off, and it definitely wouldn't hurt to blend it in to make the transition easier.