[Gracie2006]

My situation is a bit different in that I brought my yorkie puppy into a home with 4 cats. I have had the cats on supervised feeding for years, because one is on a diet. I just feed Gracie in her ex-pen with the door shut. When everyone is done eating and I have picked up the dishes, she is allowed to come out and and have free run of the house as long as I am home. Gracie has been unsupervised (mostly) in the house for a couple of weeks now. She knows where the litter boxes are but so far has not attempted to go into them. I have two and they both have covers on them. One is automated and makes a lot of noise which probably scares Gracie. As far as marking goes, I can't answer that.
You might look at yahoo groups for a cat forum to join. I bought all of my cats from responsible breeders, except for one that was a pet store rescue. You might look at the local humane shelter and no-kill shelters. They get kittens fairly often. You can also put the word out among friends, family and co-workers. Some backyard accident might get you a new friend!