Thematically I think his perfect class would Tome of Battle character like a Warblade, but a fighter/monk is more likely at this stage given the number of feats he is implied to have. Alas we still can't nail anything down just yet. Here's hoping he snatches another arrow to give us something concrete.
I've always felt that Z's insistance Qarr was his familiar was evidence enough, citing that Blackwing has shown disloyalty to V in the past by testifying at the trial. However enough people argued that his duplicity during the fight in the EoB was enough that he was faking the whole thing that we couldn't establish consensus on it.
I don't think so. Tarquin, Malack and Kilkil are there because they're members of the guild right now. If we knew some solid levels/stats/feats for Ian then he'd be on the same level as Julia, but I don't think a class and a skill are enough to go on.
I think it was added like that to just be a little descriptive and slightly humourous. If people think the description should be more accurate I can fix it.
There's two sentences there. "Feats. Stuff." The presumption that the "stuff" is an item (or more) of some sort.