The last 2 look like Activision's test accounts but the guy in first place seems a little odd probably just a developer who logged in one of the 360s at work on his personal account. It isn't really that big of a deal that any of them are there though, round 4 and 1.
ALCATRAZ is insane freak place for the first 2 rounds each one will be on his own fighting in the dark tunnels underground trying to find his way up to the surface and gather in rally point with others. while doing this you can pick limited flash bangs for free those will help you get past hords of zombies, as you can't kill them if you got down you won't die . you spawn in another freak dark spot.