Technically speaking, Vito was only a soldier, not a Capo. But that's only according to American LE and some of the US families. In Canada and Italy he was seen as a boss, and he acted like it too by not taking any orders from NY. Also to think with all the chaos that has been going on in Canada since he was gone is a huge testimony of his abilities and power as a boss.

I'm with you on Gigante though, I mean walking around with a bathrobe to fool LE is very clever, but it's not boss like.