Because of the size alone, i don't let myself give Cormier much chance although he could probably win this fight just by outstriking Antonio tbh.
As far as Barnett-Kharitonov, i think Barnett.
That would give us Cormier-Barnett on the finals where i', completely lost, but if i really had to choose, i'd go with Cormier.
I don't see him controlling Bigfoot. And I can't see him hitting harder than Mike Kyle who he trains with but gave Bigfoot everything he had right on the chin and Bigfoot still TKO ground and pounded him.
Bigfoot has decent hands. He's huge and still athletic enough to stay agressive with combos and jumping knees. His clinch work is good. He's very experienced against caged veterans like Ricco, Fedor, Kyle, Werdum, Arlovski... he's got that over Cormier as well.
He's heavy on top. And his BJJ is very good.
I know Cormier is a likable guy. Hell I really like him. But I dont see him winning this fight at all.