Why is everyone stupid so confident in it?
Tank obsessed: He fights you in a tank once. He never mentions the tank, never jerks it off like Ocelot does with his gun, and when it goes down, he doesn't give one hot shit.
Eskimo Shaman: This is true, but inuit do have shaman. It's literally a thing.
Spiritual powers: Only shows up in Twin Snakes, which is not canon, unless you think Snake is Dante.
Comes at you with his pet ravens: Literally never. The closest thing to this is, again, in Twin Snakes, where he shoots his tattoo at you for...reasons. Edit: Hell, ravens do more damage to him than to Snake.