I don't know how your cats were declawed, maybe the the method has changed? Because like 3 years ago I got to help with spay/neutering on some recently adopted kittens and one got declawed, they just extend the claw and cut at the base, she didn't even need stitches just wrapped them up for a weekI didn't know it was illegal either. But I do know the&$?@ storm that starts over the controversy. And I agree that it doesn't slow down there hunting if they were hunters to begin with. They amputate the last joint which the client is in. And there is a recovery. Where I'm sure there is pain, it would be ignorant to think there isn't. But I had it done when the animals were under anesthesia to be spayed or neutered. It is much harder on adult cats then kittens. I probably wouldn't have it done on an adult cat.
But there are a lot of ways to train a cat to scratch where you want it to. Look those up and you will find something that will work I'm sure.