I had a cat that did not like stepping on any litter I could find. I had four cats at the time. My oldest was the one I would have trouble with. She preferred using the shower floor or if she used the litter box would barely step in it, and end up peeing outside the box.
So I bought one of those kits to train them to use the toilet. One cat, my baby, did all the steps until it came to standing on the toilet, but at one point she came tearing across the room and jumped on the toilet only to find the lid was up. She has a fear of the toilet now.
The one that hated the litter box took to it right away. She was ahead of the steps, and within a few days was happily using the toilet. Unfortunately she would get on the rim, face the tank, and pee. All over the floor.
The other 2 cats were making good progress but I took down all the tools and closed the lid to keep the oldest one from peeing all over the floor.
I have no doubt that some cats can learn to use the toilet. Years ago I had a friend who had a rabbit she trained to use it.
