Hi and welcome to the forum!
I only have one cat and she's my first, so I can only share my experience with her, but I'm sure others will be along to add more helpful hints.
1. How do we insure the cat will use the litter box?
I adopted Holland when she was still a kitten - about 5 months old. She was already litterbox trained, and it's my understanding that unless you get a kitten that was taken too early from its mother, this is something the mama cats teach.
2. Do we need to keep it in a single room for a week to let it adjust?
Depends on how big your home is and how old the cat is that you adopt. If you have a lot of space, I'd probably say yes, it's a good idea to introduce the cat to the place a little bit at a time. If you get a kitten (under a year old) I'd say it's a good idea no matter how big your home is. I had a 2-bedroom condo when I adopted Holland, and she was allowed wherever she wanted as long as I was home. When I went out, I closed her in my bedroom with food, water, litterbox and some toys.
3. We have nice furniture how can we keep it from scratching?
Scratching posts! There are several types available - carpet, cardboard, sisal... different cats have different preferences. I think I lucked out with Holland - she has never been interested in scratching anything but her post.
4. Should we have it declawd?
Please, please don't have your cat declawed. The procedure is comparable to you having your fingers amputated at the first knuckle, and it removes your cat's ability to fulfill their basic scratching instinct. Some declawed cats also develop behavioral and health problems. Keep the cat's claws trimmed - this was a difficult operation when I first got Holland, but with time she learned that it doesn't hurt her and I can now sit with her on my lap and clip, clip, clip, it's done in less than a minute. There are also soft claws available that you can slip onto your cats claws, as well as furniture protection such as sticky tape.
5. Once the cat is use to us can we move the litter box from upstairs to the downstairs closet area? Will the cat find the litter box?
Again, I've never had a problem with Holland when I've moved her litterbox. I always make sure she sees me move it, so she knows where it is. If you have a rather large home, I'd consider getting two litterboxes anyway.
Welcome again, stick around and please post pictures of your little one when you get him/her!
