1) How hard is it to train them "not" to scratch on furniture and bedding and is it really horrible to declaw them?
You can use a squirt bottle to train them not to scratch furniture. They don't like it AT ALL, so if you do it enough times, they'll probably stop. And if you have a scratching post for it, you can get catnip and put it on the scratching post. It should work. And about the declawing thing, I really don't think it's a good idea at all. If the cat were to escape and get attacked by a dog, they'd be in trouble.
2) How hard is it to really give them a bath? brushing?
I don't give my cat a bath, but I would imagine it's pretty hard to do it. And my cat loves brushing and the flea comb.
3) Do they easily go to the litter box?
Yes. Before we got my cat, he was a stray. When we brought him home, he found it and used it with no problems, and we haven't had any problems with it so far.
4) Do they really find delight in houseplants?
Yes. My cat likes to chew on those little things of grass you get at the pet store.
5) how much do they really punce around and jump on shelves and stuff?
A lot. He gets on top of things where he's not supposed to be, like fish tanks, so the squirt bottle works good for that too.
6) If they try and play too rough, is there a good way to train them not to bite or claw?