"Yeah there's a time limit per map based on battles you do (I think non-crowd enemies you kill) that wil reset the map (but not the rupees/EXP/weapons/items) you collected once you hit zero. Clearing maps with Owl statues on it removes the reset from the surrounding maps. At least I think that's what the tutorial is telling me, haven't had a chance to play through one yet."
Well at least it's not a full reset, so there's that. Still no word on the difficulty, though.