Hi!
You can't expect to get any better with the limping, that's the problem with spina bifida: she was probably having the worse type of, which means this part of the nerve(s) is not connected!
I suggest balance exercizes with orthopaedic boots made for her, to stabilize the ankles/feet, training of the remaining muscles on the same chain (see Kapandji). PNF is a good idea, add a lot of exercizes for hip and knee control.