I once had a cat a missing front leg and a missing eye. He was caught in a trap.
He was able to use the litter box, but unable to cover up his poop afterward. It wasn’t a big deal. As far as the mobility, she’ll either learn to walk on what she has, which is certainly possible, or live a sedentary life. It is what it is.
My immediate concern would be whether any internal organs are similarly unformed, especially the heart. What you see on the outside may be a reflection of what is going on on the inside.
Cat scan Stat.