The verb is correct.
You've identified the complete subject. Are you supposed to identify the simple subject?
Kim's dog and her cat are good friends, most of the time.
subject: Kim's dog and her cat
verb: are
3 answers
Find the simple subject
Kim's dog and her cat are good friends, most of the time.
answer: dog and cat
Kim's dog and her cat are good friends, most of the time.
answer: dog and cat
Yes.