No. Blackwing's card specifies "When you defeat the last Monster in a room..." meaning that it has no effect when battling other players.
Only one card is flipped.
Currently the only ways to boost this card (called Secret Crush) is through using Get Angry or having Vaarsuvius target it with the Buff Spell shtick. There might be other ways in future expansions.
It is not automatically boosted whenever she's fighting one of them; it merely gains a +4 bonus towards fighting them when it IS boosted by some other means (such as Get Angry). The intent is that when Haley "gets angry" at Elan or Nale, she's much better at fighting them--"Hell hath no fury like a woman scorned." If it is boosted by Get Angry on a turn when she's not battling Elan or Nale, the Boost has no real effect.
No. The Room Deck means the deck with the words "Dungeon Rooms" on the back, not the Xykon's Lair deck. If you need an explanation, the magical darkness in Xykon's Lair can't be penetrated by mere darkvision.
Each monster is moved individually, so yes, you can do that exact thing. Further, if the room has stairs going down, you could move Nale and Sabine down, Thog left, and the two goblins right.
Nope. Once Double Cross is played, that player is no longer assisting the battling player, they are assisting the Monster (or other player). As a result, they are no longer effected by There is No "I" in Team, which specifically says that only those players that were assisting the losing player lose 1 Wound--and the Double Cross-using player is NOT assisting the losing player anymore.
There is one semi-exception: If the Player A is fighting Player B, and Player C is assisting is assisting Player A. Player C then uses Double Cross so that he is now assisting Player B. Now, if Player B loses, Player C would be affected by a There is No "I" in Team card played on Player B. If Player A loses and the card is thus played on Player A, then Player C is not affected, as he ended up assisting the winner.
Multiple There is No "I" in Team cards can be played, yes, but the exact situation you describe is not legal, since Roy was no longer assisting a player at all.
Yes, he can flip both. At the end of the battle, he loses 1 Wound, because the first shtick to be flipped was Boosted by the second copy (meaning that you don't lose 1 Wound for using it), but the second shtick to be flipped was not.
Vaarsuvius was incorrect here. "After the dice were rolled" means immediately after the die roll, before moving on in the battle sequence. Making the die roll is Step 5; giving Loot to players that assisted you is part of the Aftermath, or Step 7. Haley cannot play Eternal Gratitude until Step 7; the card says to play it immediately AFTER any battle (the Aftermath, as its name implies, is after the battle). Vaarsuvius cannot back the sequence up to Step 5 once the battle is concluded. As a result, he cannot Double Cross Haley after she plays Eternal Gratitude.
This is probably one for the FAQ, though.
Durkon can't roll a 14; Divine Intervention of Thor specifically states that it works when rolling the die "in battle". Therefore it has no effect on the Shrine of Thor.
Yes.
This is, in fact, the very best way to defeat Xykon. It is absolutely legal and has been suggested by us as one of the primary solutions to the "invincible Xykon" problem. Good planning = win.