The Sox catchers are basically a case of range of outcomes ...
Leon has the smallest range of outcomes - a good receiver who is just a poor hitter. A team with our offense otherwise can carry him, but he is a weak spot. It is what it is.
Swihart has the largest range of outcomes - just a lot of natural talent and injuries have gotten in the way. There is a better chance he can be a plus offensively and a solid defensive catcher. But between injuries and a lack of major league performance, we're just going on eye test
Vazquez is somewhere in the middle. Defensively, he is excellent. He is a good enough receiver/gamecaller. Is it possible that he can hit more like the guy who we had late in the season? If so - then he is a well above average starter. That a streak like that is inside of him (and that he has flashed it multiple times) makes him at worst an okay starter/excellent jobbsharer. The one thing I see offensively is that he does put good at bats together, and he is a tough guy to strike out. What varies is whether he can make hard contact consistently.
I would suspect Cora and Dombrowski would prefer if the offensive form Vazquez showed in October was relatively sustainable. A .270/.330/(who cares) with his receiving would be a terrific outcome.