Looks like you have a handle on this. You have support of the rest of the team, no prize money issues and it appears "Right" is on your side.
My only comment is your e-mail to your teammate may contain TMI, Too Much Information. I know it's hard not to describe everything that came up, however, my suggestion is to keep it simple, eliminate where you can the emotion and communicate at a high level. I know Nikki was upset and so were you. I know that he was being derogatory to a teammate. I know you also had something to apologize for and, through your actions, did the right thing which demonstrated to your teammate that there is courtesy required on the lanes, providing he was paying attention.
My advice is to simply state the facts, briefly, and ask your teammate to act accordingly, showing the same courtesy to others.
While I don't like ultimatums, sometimes they can be effective. I'd close your communication with a statement letting him know that if an improvement is not made, he will be dropped.
Yep, that's a bit harsh but if that is what it will take, so be it.