Sounds as though you shouldn't have cats--you don't really seem to be a cat person.
Both have developed the bad, bad, bad kitty habit of scratching the furniture.
Scratching anything, furniture or anything else is not a bad kitty habit...and definitely not a bad, bad, bad kitty habit. It is an instinct...something every cat does. People for whom this is an annoyance SHOULD NOT HAVE CATS.
I really do not like the idea of declawing a cat. It is in the nature of cats to claw things...and cats without claws definitely are missing out on a lot of cat enjoyment. I understand that for some people it is the only way to work, but I just hate the idea.
No advice I can give you except keep the old furniture until they die. When they die, buy new furniture and get a few throw pillows for pets.
But I suspect that ain't gonna be the solution you go with...and it looks to me as though these poor cats are gonna pay a price for having selected the wrong person to live with.
By the way, I accidentally clicked the "report" tab. Pure accident. Sorry. Hope it did not get reported. Nothing to report...good post although as you see...I am not happy with what probably will go down for the cats.