You're getting good answers for everything, but I just wanted to chime in as far as canned cat food goes.

You're probably thinking of the cheaper stuff that looks like vomit and smells about as good. There's canned cat food now - and not much more expensive - that looks like what you'd pour out of a people can of stew/soup. It doesn't smell like anything but whatever food it is - chicken, beef, whatever. The extra cost is worth it for ingredients I can visually identify and for food that doesn't make me want to be sick.

Also for your last question - I think they make rubber tips you can put on cats claws, but as long as they have scratching posts they generally leave furniture alone. If they don't, a squirt bottle can work wonders. Mine love those little cardboard scratchers and they both learned pretty quickly not to scratch the couch.