All Expert Challenges already covers all Attack Pieces and all Pi'illos (You need to have excellent with each attak AND you have to revive all 52(?) Pi'illos to obtain one of the attacks) and is a category that I plan to run one day (and by saying this I must do it now as a promise). Quests aren't necessary, nor are beans.
If you want a 100% run, then I would probably do:
All Expert Challenges, which includes all attacks and all Pi'illos All Beans, all badges, all blocks. All S-Ranks for the Skillathon/Broque Madame challenges and all puzzles for Kylie Koopa. And of course All Bosses + X Bosses (which subsequently requires all Ultibed Parts)
Basically, all trackable things that can be undone. You can only track blocks at the end of the game which sucks, but it IS trackable. This is very very very arbitrary though as there is no official 100% list.
Though do not expect either All Expert Challenges and especially not 100% to ever appear on the leaderboards. Maybe expect All Bosses, I do want to run this and this isn't too arbitrary in my opinion. [I do have a bad habit of not running for a bit after PBing so expect a few months before I actually start doing All Bosses runs (I am including the X Bosses)]
