Desmond is the ALT MIB....but not yet by The Lost Candidate

I've read a few of the recent theories suggesting that the MIB has manifested himself as Desmond in the ALT timeline and that his motives for gathering everyone at this concert is to kill them. I think there's something solid there.

But the missing piece in this theory is how and when the MIB took over Desmond's body and got off of the island. What if he hasn't yet? We're obviously counting down to a few significant moments both on and off of the island and my prediction is they will all happen at exactly the same time.

On the island, Locke/MIB is planning to utilize Desmond to destroy (sink?) the island. Presumably, this will allow him to escape. Perhaps in conjunction with sinking the island (by throwing Desmond into the light cave?), the MIB is able to manifest himself as Desmond in the ALT timeline?

Perhaps ALT timeline Desmond knows this - the same way that he knew that Charlie was going to die. And he knows that this will happen at the exact time that this concert will be taking place. Rather than gathering the 815ers at the concert to kill them, he's gathering them to kill him. Much like Jacob touched the candidates so that they'd appear in 2007 at the time of his death, what id Desmond is ensuring that the candidates will be present at the moment the MIB takes over his body in the ALT timeline?

There's been a lot of talk about Jack or someone having to make the ultimate sacrifice to save the island or save the world. What if, rather than Jack, it's Desmond who's making the ultimate sacrifice? It wouldn't be the first time. I still think that there's something happening with the blood on Jack's neck and the fact that he's the centerpiece for the entire series. My guess is that he's the one destined to kill Desmond/MIB. 'See ya in another life brutha' and all that....

This is the first theory I've posted and, with the finale on Sunday, likely the last. What do you guys think?