If you do decide to have your broody hatch, you're in for a wonderful experience! But I can understand your concerns about integrating the chicks and Mom with the flock.
I would advise you to set up something for her ahead of time, so when she is finally sitting on eggs she is protected from the rest of the flock but they can still see each other. For some reason other hens seem to want to crowd in on a broody when she's sitting on eggs in a nest in the coop, with the result either being more eggs being laid along with the ones you've chosen or broken eggs from the jostling that goes on when two hens are maneuvering in the same small space. There's also the added risk of the others bothering her so much she just gives up.
This is what I set up for Agatha the first time she went broody, and it worked very well. It's just a large dog crate that had a door on the side and another door on the front. I opened the front door and wedged it up against her nest. Instant broody pen. As you can see, she was very comfortable and the other girls, while curious, couldn't get in to lay additional eggs or harass her. That's Daphne looking in.
At first I set up this pen for brooding shipped chicks outside. Again, the girls could see in and they could see out, but they were safe. By 4 weeks the chicks were integrated with the adults, with very few problems.
Right after they were "evicted", Agatha went broody again. This time we picked up her nest, put a dummy egg in it, and moved her into that same pen. For the first couple of days we put landscape fabric around the sides of the pen until we were sure she was settled and going to stick to the nest. Then it was removed so she was confined but not totally isolated.
This was just an old dog x-pen that I had from my dog showing days years ago, but it was perfect for what we needed. From now on any broody we have will use it just as Agatha did. But you are far less likely to have the older chickens killing or bullying the younger ones if they can see them and the chicks and Mom just become another part of their environment. The bonus is because it's pretty big, the chicks have a chance to get a little bigger and stronger before they become part of the flock.