The poor thing! I would never patronize that vet again, and would tell everyone you know the same thing. I have never personally known a kitty declawed on all four feet. She may still be able to leap onto a cat tree - if her feet ever stop hurting, that is, but she won't be able to climb. She may b able to run just fine. Again, it depends on if her feet still hurt after she is theoretically healed. I hope she heals, and isn't scarred for life physically or mentally any more than necessary, and that her feet stop hurting.

Remember that, if your cats act aggressively toward her, her only defense any more is her teeth, and as cat bites can be nasty to both humans and other cats, so I'd introduce them very carefully, and have a spray bottle handy.