I think repotting into 5 gallon pails of fresh soil would be a good idea.
Throw them under a halide as soon as the new growht looks like it is improving, and give them a grow fert for a couple feedings, then switch to a bloom fert for a few days before cutting, like you had planned.
I just got 7 moms in similar shape- better tended, but certainly root bound and showing the associated signs of def and stress. That's what I'm doing for them, but my foliar is the GH micro mixed weak, and my ferts are conucopia bloom with added fish emulsion for vegging. So far they are looking promising.