Unfortunately, now that the females have been with the males, they no longer need them in order to have more fry so if overcrowding is the potential problem, I would move the males to the smaller tank and keep the females in the larger tank to accommodate the future fry.
As for the fry with bent spines, they really should be euthanized as they are not going to live a healthy life. Malformation of the spine can be from genetics, disease or malnutrition so without knowing which it is, they pose a health threat to the other fish. If these were wild, those fish would be eaten first by other fish. That's Mother Nature at her finest.
They really shouldn't be part of the future genepool. (imo