I sympathize with you. My first yellow lab mother did just what yours did. I isolated her in a 10G, she spat her fry, I returned her to the 75G soon after, and in short order she was holding again!
For the second batch of fry, I stripped her as soon as they were free-swimming and put them in a breeder net. I kept mom in the 10 and tried to get her to eat and grow, but she really didn't grow (still about 1.5") although she did gain a tiny bit of weight. I don't remember how long I kept her out, but after a few weeks or so I moved her back to the 75 so that I could release the fry from the net.
I was pretty worried about this fish when she turned up holding again so soon, but she managed it fine and is doing well in my main tank. She is taking a breather (hasn't held eggs in 3 months) and has grown slightly. She is smaller than my other labs and may just be a small fish.
In your place, I would strip Mom #1 as soon as I could, so she would start eating, regardless of where I put her afterward. If I didn't really need the fry, I would strip the eggs into the main tank.