Actually, that's fairly dark and short-lived, so I'll keep it vague. In short, he got his revenge and obtained some items of value at the same time. Maybe not quite an accident but, for him, a happy coincidence.
Nope. Flag has been his name forever. He however was not born into a clan, tribe, or family of any kind so he has no clan, tribe, or family name to add to the end of that. Jokingly, he stole "Del Monte" from the banana company and uses that on things that require a last name.
It's kinda wild, TBH. All hell broke lose in the event that "injured" him, but as that was his doing, he wasn't exactly surprised by it. What he was surprised by (well, the first couple of times anyway) was coming to at Carmen's feet in an abandoned bank and getting medical help.
I do not believe that we discussed ever writing it out, so It was never planned. I won't say no though.