1: Leather Armour - ( +1 Health) / Brown Die)
Is this intended to grant the wearer of this equipment an additional Brown Die for every defense roll?
2: Avric Hero Ability - ( Heals all Heroes in range of 3 for Surge : 1)
A: Is this ability active on ALL surges, regardless of if they have already been used?
B: Can this ability be stacked, upon rolling multiple surges?
The ability in question grants "(Surge): Recover 1 (Wound)" to all attacks made by heroes within 3 spaces of Avric. This is a surge ability. Normally surge abilities are found on the weapon you're using to attack with, but sometimes they come from skills or, in this case, Avric's hero ability. All surge abilities follow the same rules:
1) you must spend a surge to activate the listed effect.
2) you may only spend 1 surge per surge ability on any given attack.
3) surges spent elsewhere cannot be spent on this ability.
So, to answer your questions:
A: The ability is always available to any attacking hero within 3 spaces of Avric (as long as Avric is not KO'd.) Surge abilities are not "active on surges" they are activated BY spending surges. So the attacking hero can always choose to spend a surge to recover one wound, but if he doesn't spend the surge doing that, he doesn't recover the wound.
B: The ability can only be used once, like any surge ability. You cannot spend multiple surges to recover multiple wounds on the same attack roll. However, if you attack twice, you could in theory spend a surge from each attack to recover 1 wound each.
3: Spiritspeaker Skill - Vigor (Each attack recovers all heroes 1 fatigue per surge)
Similar to question 2A, is this passive active on all surge rolls, regardless of if they have already been used?
Same as Avric's ability, above. Surge abilities are not active on "surge rolls." They are active on an attack. If that attack rolls no surges then you have nothing to fuel the ability so it obviously won't go off. If you do roll surges, then you can choose which surge abilities to spend them on.
The skill is passive in the sense that this surge ability gets added to every attack the Spiritspeaker makes, but he must still roll and then spend a surge to use it. He cannot spend more than one surge on this ability per attack.
4: Death On The Wing
A: Encounter 1: Is a Hero defeat condition viable if they are standing beside each other while encaved by boulders, the side of the map, and enemy minions?
Yes, the heroes lose in this condition. The heroes lose if any one hero is surrounded by "figures, boulders or the edge of the map." Other heroes are figures, as long as they aren't KO'd. (If they are KO'd, they are replaced by a hero token, and therefore there is no figure in that space.)
What are the conditions? May they be moved of free will if there is no one in the room? Must they be left where they are, until someone enters?
The guards in this quest may only be activated if a hero or monster is on the same tile. If there is no hero or monster on the tile, the guard may not be activated. If there IS a hero or a monster on the same tile, the guard MAY be activated. The hero player controlling the guard may choose to have him do nothing, if he likes.