Anyone who is a real fan has all the optional characters, thats kind of a gime
What are the most jobs that you've mastered for the most characters in this game?
I've never had anyone master all the classes. Some people have come close, but I usually prefer to start a new game than continue grinding JP out. If you count all the mastered classes across all my saves it is in the hundreds (I've beaten the game at least 8 times)

How many of the items have you collected? How about teh rare items that can only be stolen or poached?
I have all the stolen items, but very little of the poached ones. I don't use them much, and I'm not in the habit of collecting for the sake of collecting.

How many of the side-missions fromt the bars and pubs have you completed?
Did them all on my first playthrough of the game, but never do them on any other playthroughts.