After bashing my head against the second triple quest for days, I finally discovered something interesting - you can take preparations! I did not know this! It's not at all clear, considering that every other dungeon and quest in the game has you pick your class first, then takes you to a page for preps, rather than requiring that you actually click on the preparations tab on the right.
I suppose I made the first one a bit tougher for myself than it should have been, too. Ugh...