Nope. No adult feed. The mother will feed them and all the available feed must be chick starter, All Flock or Flock Raiser. No layer feeds. Hence the need for oyster shell.
The mother will take them out of the coop to the run. I strongly recommend you give them more space.
If the mother cannot...
Separating her should not be required. The broody should continue to have access to the flock, feeder and waterer.
Is it just the two hens?
If so, she will likely be highly tolerated by the broody as they would be strongly bonded.
If you haven't done so already, put out chick starter, Flock...