I would say you should be fine, as long as the chickens get along normally. We had to give our broody a corner to herself because one of the other hens was constantly harassing her, otherwise we'd wouldn't have seperated them. They definitely are good for sitting time if they get along... once they hatch just check in on how they are doing, but they should be fine. You'll be amazed at how good a job the hens can do making sure their little ones are taken care of!
Depending on how many eggs your hens hatch out you should be good till they are at least 4 to 6 wks or so for room in your coop. Your coop should house up to 8 adults pretty well, so other than cleaning a bit more often you should be fine till spring. So you should have time when the weather improves to figure your new pen plans out.