The account does, but the Guest account doesn't get to save the points that they get.
Yes you can!
yes
Yes
unfortunately it doesnt The PS3 and Xbox 360 do have online split screen
Call of Duty Black Ops is four player split-screen, and 2 can play split-screen online.
Both.
yes you can
No only on campaign is split screen
yes
WEEB
You can play online in Call of Duty Black Ops PS3 using the online split-screen support.
Split Screen Private Match: Yes Split Screen Online: 2 players Split Screen Zombies: 2 players When playing online you may have up to 18 people in your party, as long as you are all playing on separate consoles.