Need help with a cat issue.

[herding cats]

7. I use two sided tape to keep my kitties off of furniture they're not allowed on.

Cats, at least mine, find it repulsive! In your case, since it's new leather and all, maybe single sided tape doubled over to stick in place? It shouldn't hurt the leather that way, and will be easy to remove later. I'd try something like some painters tape or some other not too sticky tape to be on the safe side.

Once you train them that it's not a nice place to sleep they usually forget about it in a few days and move on to a new area.

If this doesn't work they make caps you can glue onto your kitties claws, but I find them to be a nuisances. I just trim my kitties claws and try and discourage them from being attracted to places I want protected. Like with my tape trick.

Note: Don't trim or cap your kitties claws if you let them outside. They need their claws if they go outside for self defense and to be able to escape threats.