Heather I'm glad that you finally were able to find Kelly. When I introduced Gracie and Gabriel to my other cats I started off using a dog kennel crate, medium size. This gave G&G a place to feel safe and secure while getting used to the other cats. I would then let them come out when Mark and I were home to supervise them. I was able to get a small litter pan, bedding and food and water dish in the kennel crate. Then you could do supervised "visits" with Boo-Boo. Just a thought. Again I'm so happy that you were able to find Kelly.