Id love to see a pic of your girl, Bobo. It sounds like you’ve done a great job getting her hocks looking good again. That’s no small feat in a rex!
Im glad LPT saw this and suggested the bath mats. I think the added benefit with those is the outer lay is a soft, mircrofibre fabric that is non-abrasive. Just by chance, I did a search as I was trying find name of that outer fabric. I came across super size bathmats on groupon. That might be an option for you. Or a series of smaller ones that you can just switch out the soiled ones as needed.
Another option is VetBed with some puppy pee pads underneath. However, that might be a little more abrasive.
Do you think her incontinence is related to the EC or just general mobility issues? The urine makes the battle more challenging if the fur on her feet gets wet. That could certainly cause some fur loss.
If the quick in her nails is long, you might only be able to do small tip trims at a time. Usually when you press down with the clippers, they’ll pull back if you are too close to the quick. (She may do so regardless if she is feeling sensitive with her feet and/or some arthritis). You might only get away with regular tip trims, but the quick is supposed to reduce over time when the nails have frequent trims.
A strong light directed behind the nail definitely helps gauge where the quick is. There are even some clippers that have an in built light. I just use a small torch myself. There is always vet clinics or a rabbit rescue that offer nail trimming services if you find it difficult to do yourself.