#1 is not false. Vazquez was in fact the primary catcher.
#5 You are absolutely right, but the pass throughs occur because that player's salary makes him not worth picking up, which is still my point. If Sandy Leon is so good he transforms a pitching staff, than $2.5M is a small price to pay. Or consider that the BoSox are currently paying him $2.5M not to play for them. There is no way, no how putting Leon on waivers shows how great a catcher he is.
I like Sandy Leon, and I think he is a good catcher. But management--Cora, the pitching coach, DD, et al--don't like him that much and they are paid to make good judgments on players. And last year, just as you say, they saw him start 87 games for the Sox.