The trouble with staying with me - I have not introduced cats to each other before but I know the best way is to keep the new one in a separate room & introduce very gradually until they get used to each other, which can take a while. The only room where this would work is my bedroom, and it's going to freak my cats out if they can't retreat in there when my mom is around, so this would have to be reversed (my cats locked in the bedroom and visiting cat having the rest of the apartment). Visiting cat is 15 years old and unlikely to change her attitude toward other cats, especially in only nine days. She also is missing a front leg, has arthritis, and is tiny. If they got aggressive with each other she wouldn't really stand a chance. If sister's cat stays here, I'm thinking the best route would be to just keep my cats in my room the whole time.
The trouble with a pet sitter - it's an unfamiliar person in an unfamiliar place. Sister's cat has stayed with my mom in this apartment a few times before I moved in, and she was initially our family cat so she knows us well. Sister is getting recommendations on a sitter but of course it does also involve trusting a stranger - not only with caring for her but giving her meds every day (cat has health issues but is not contagious).
Do you think it would be less stressful for all involved for sister's cat to stay with me, or to be taken care of by a pet sitter? Have you ever used someone you didn't know as a sitter? How did it go?