Spoiler Free Darkest Dungeon advice?

I've done nearly everything there is to do, except entering the... Darkest Dungeon. I've been farming quirks for a long time, but now I'm not sure if I farmed for the wrong heroes. So without any spoilers who heroes I should not bring, what DOTs will I be encountering, what curios items are most common, and is shuffling a big issue? Is there a question I should be asking but didn't?