I'm going to try to get my roommate to give away her kitten
How will you accomplish this?
I'm going to tell her that the kitten ran away.
That's mean and rude of you to do. She's likely close to that cat already. Don't do that to her.
Everyone hates me and I'm doing this because that cat is really annoying.
You sound very insecure and that is not the cat's fault. If you need help you should seek mental help instead of hurting your friend.