Sounds like you could use help from Jackson Galaxy, My Cat from Hell guy.
They obviously need a release of their energy in some other way. I don't know what that way is, but Jackson would know!

As for the scratching of the furniture, maybe try the sticky paws sheets. I don't know if this would harm the actual leather or not though. But we use this on our speakers and it works.
Trimming nails on a regular basis helps too.

I am glad you are trying to work through this issue and not just giving up on these kitties.

Good luck!!