Unfortunately, the shelter will not keep the mama with the kittens that long.
They will remove her and spay her as soon as the kittens can eat on their own. I don't think being in our hall bathroom would be any more traumatic than being in a cage in a room with other cats, kittens and dogs like she will be in the shelter.
We did take the last mama cat back because she did not use the litter box and she tried to leave the house every time there was an open door.
If the problem continues, we will either keep them shut in the bathroom more or take them all back to the shelter - I would not separate them this early, nor would they, but I would prefer to keep her with them until they are at least 8 weeks old and they will not do that there.
I was hoping for suggestions on ways to socialize the mama with our other pets if possible.