Osama? Usama? These are anglicized phonetic approximations of a name properly spelled in Arabic. I'm sure there's some organization that sets the "convention", but it really doesn't matter much.

I'm really sorry he was dead when they tossed him over. A nice keelhauling along the full length of a CVN's barnacle-encrusted bottom would be appropriate, topped off by being sucked through her screws.

Whatever. As of today OBL/UBL = shark sh!t.