Well, here's an update:
He's doing fine, Shayna is getting better, I think she realizes that if she hits him when he bugs her that he stops. He did however start sneezing last Friday(a week ago), and we took him in and he's fine, he just has allergies. My mom just took him into the Human Society(where we got him) for a 2 week checkup and he's gained over a pound in 2 weeks lol. I have stoped keeping him locked in my room at night though, one night I went to bed at like 1(had summer school), he kept me up till 2, and then when I told my dad(who was the only still up), he just said to try to deal with it the best I could. Well Cosmo started clawing my head several times, before viciously attacking my arm(blood scratches). And it also pissed me off that my room was 88 degrees(cause the thermostat for the house is in the always cool living room, and me in my subcompact room with all the electronics, it's a furnace)so I got my pillow, I went out to the family room, and slept out there and let him do whatever the hell he wanted to do. So then I just left my room open everynight, he knows his way to my room for food and stuff, but my mom didn't like it cause Cosmo was doing his drive by attacks to her and my dad(my dad thought it was great though, cause he slept through it and Cosmo slept on his head), but I never closed my door again, but he's fine now.
That's about it...