The third option is the safest one as long as he's smart enough to find a way to not leave a trace about the contract.
The problem with the thrid option is that the bully is highly unlikely to know that it was from you. Part of revenge is you want the person you are getting revenge on to know you have got your revenge. Looking down the barrel of your gun just before you pull the trigger fulfils that. Especially if you just blew off the head of the person next to him. Adds a lot of gravitas to the whole situation.
No problem, just teach the illegal immigrant the following sentence, to be repeated at each shooting: "The Kingslayer sends his regards."