I am sertain what Chaozi ends up becoming exorcist. He is still too minor to be sacrifial lamb.
Crowley certainly would get powered-up after sucking Noah blood. But that will turn him to the true vampire (a power-up indeed).
And Lavi will se left behind. Fighting Tiki, perhaps (Since Road was interested in Allen. And if Allen is traitor_Noah successor, they will be fighting over the Ark's controle). But maybe it would be Lavi vs Road, and finally Tiki vs Allen)
I agree, it seem like traitor_Noah successor will use Ark's power to return everyone (Everything in Ark is getting copied somewhere, so there might be traces of left). Or maybe that shiny thing that fled from General somehow helps them.
<feels sowwy for his Engrish>
There is a sig. You just can't see it.