My sister's two cats are declawed as well (she met them that way), and they're both fine as well. I've even lived with them for a few months, so I know first hand. They are half-brothers, and have been together all their lives. Both boys are only front declawed, and neither has had any litterbox problems in the years I've known them. They are also indoor only. Minion doesn't bite, likes to knead, and definitely knows how to use his back claws if he's unhappy. Especially if you have to pick him up, because he doesn't like that at all. Unfortunately, in the last month he's picked up the habit of sneaking out and trying to sneak outside. Bad kitty! Mouser is a biter, but really only when he feels like it, because he likes it, apparently. Once all I was doing was using the computer with him laying on the bed near me, and all of a sudden he reaches over and chomps down on my arm! Weirdo. Also, sometimes he does it so quickly you aren't sure exactly what happened! He also uses a front paw to hit the dog on the head. I think he's "right-pawed".
My two kitties have all their claws. I clip their front paws. Some people clip the back claws, too, but I've found that I don't need too, they take care of it themselves. These are my first cats; growing up we only had a dog. So, naturally, I was wary of their claws, as well. I've had Loki for 5 months, and Possum for 3 months. Neither has scratched me more than superficially, and it was all accidentally. A few days ago for the first time, Loki decided to stretch his claws out on my leg, so I took his paws off, and told him, "Mommy's not a scratching post, honey!". Later, I clipped his nails. Loki has never taken a swipe at me. Possum took a swipe at me once, but it was the most pathetic, gentlest swipe ever. I'm not even sure his claws were out. The poor guy was scared and upset because I had taken him to the vet, and back at home I had to then put some Revolution on him, and he was freaked out. It was just a little warning for his benefit, really.
Both are adult cats and understand when and when not to use their claws, unlike kittens. They don't destroy my furniture. Well, they did destroy the bottom of my brand new couch. Sigh. There's also a rough spot on my boxspring, but I've almost fully gotten them to stay away from that. But there's lots of things that they could potentially scratch, and I've had no other problems.
When I was first thinking of getting a cat I was living at my Mom's house. She told me that if I were to bring one to live in her home the cat would have to be completely declawed, front and back. I was actually quite shocked at her rule, knowing her. So, I researched declawing and ended up deciding that I couldn't do that to a cat, and I decided to wait to get one. I got Loki 10 days before I moved out of her house, and she had no problem with him. Recently, my sister and I have been trying to convince Mom she needs a kitty (mostly jokingly), and the subject of declawing came up. She told us that she "could never do that to a cat," which is what I thought her position was on the subject in the first place! I've determined that she only told me that my cat would have to be declawed to live in her house because she didn't want an animal living there, and she figured I'd decide on my own not to get a cat because I wouldn't want to put a cat through that, either. If I had agreed to declaw, she probably would have come up with something else to deter me from getting a cat.
If you get the kitty you are thinking of, I truly doubt the claws will be a problem, and in a few months you'll be laughing at yourself for being so worried about them. I know I am!