I can't really give advice on Chance because I have no vet training, but if it were me, I would try the corrective shoeing and just see how it goes.
My very first horse I'm sure would NEVER have passed a vet check, he had one front pastern that was almost totally fused in place, but he was a super first horse and I had him until he died recently at age 26 of colic. He was able to be lightly ridden the entire time I had him. Sometimes nature has a way of healing things, and it may not be perfect or pretty, but the horse can still be serviceable sound for many years.
I hope that is the case for Chance. You can always try to find her a home if she stays unsound, so it might not hurt to try the shoeing and whatever else the vet recommends for a while and just see if she heals.