My understanding, based on the rules, was that you DO reshuffle the Loot and Battle Decks, but not in the middle of a turn. So that if you run out of Monsters in the middle of filling up a high Battle Size, the deck is not reshuffled until the end of the turn. Same thing with the Loot, which would mean that when the Monsters vanish with Xykon's death, you deal out Loot into the dungeon until the current deck runs out, then you're done. This one will need further behind-the-scenes consultation, though.
You do, however, deal Loot from the bottom of the dungeon up when it collapses, to prevent people from hanging around the Entrance to grab free Loot while someone kills Xykon, then grabbing the bonus for being the first to exit, too.
Cure Additional Wounds can be used at any time. Note, however, that if Durkon is fleeing the dungeon, he cannot heal himself until after he has reached the Dungeon Entrance. He could still heal others, however.
Also, you can't flip the shtick between the time you learn you are losing your last Wound and the time you actually lose it, or any other silly ways of trying to retroactively prevent fleeing the dungeon. Use common sense.
You may ask for assistance from any number of players, except those who you are battling in Player vs. Player combat, obviously.
No, you are playing this incorrectly.
A Monster attacked at Range that cannot respond still has a Defense score, and you must still beat that Defense score with your die-roll-plus-Attack. The only difference is in what happens if you FAIL to defeat the Monster. If you lose a battle against a Monster without sufficient Range to fight back, you suffer no ill effects. You don't lose a Wound or get paralyzed or anyhting else; it's treated like a draw.
Incidentally, based on your question, I can see that you are playing the rules on battling without a shtick incorrectly, too. If a player battles without a shtick, they do NOT lose automatically. They still roll the die, they just don't get to add bonus to that roll. A win by a player without a shtick does not defeat a Monster, it counts as a draw.
No, you can only target Monsters in one room at a time. If you can taget more Monsters than there are occupants in the room, the excess are wasted.
Just the undead.
No, Xykon isn't targeted by Turn Undead.
I'm not understanding this question, sorry.
They can choose another shtick before they roll the die. If they don't have another shtick available, they must battle without one.
Top.