He should do okay in the basic stealth missions & the fights, probably even better than the assassins. He's basically a magical LotR version of them. Big issues come from the fact that he can't Captain a ship so III, Black Flag, and Rogue are gonna be tough. He hard fails those when he's gotta navigate through a storm, as that is canonically how the Jackdaw went down.

And in the bonus, they've all got insane stealth feats too, but he's got that temporary invisibility going on. Is it all at once or taking turns 1v1 like a Jean Claude Van Damme movie? Some weapons, such as sleep darts, guns, and the like could cause him major problems.

Trying to get them all at once, yea he'll probably get one or two but then he gets to deal with defending from all angles while also being shot at with firearms. Assassins take it. Even with his enhanced strength & agility he can still get fucked up with a surprise hit from an Orc, and there are a lot of highly trained guys with unconventional weapons.

1v1 right after the other however, Talion probably takes it unless Ezio has the Apple of Eden. Just as skilled as any of them in close quarters, with enhanced stats and some weird powers on top of it.