I'm also interested in how Banish works.
1. Banish with no spawn tile:
The FAQ had this to say about HATE:
HATE
Q. If a Hero attacked by Hate does not have any
unexhausted cards, does he automatically take 2 extra
Wounds?
A. Yes. A Hero can’t choose an option he’s unable to fulfill.
However, remember that the defending Hero may still be able
to exhaust his Hero Card to prevent the extra Wounds.
By that example, I think it's safe to assume that if there is no spawn tile, 2 extra wounds are automatic.
2. When to apply Banish's effect:
By the card's wording, there's no condition for hits/crits/wounds, therefore I believe the effect always occurs.
However, that raises another question:
3. If there is a spawn tile, And a monster is attacked with Banish, can the targer always choose to get banished, thus denying the hero the reward/quest completion?
This applies whether the monster was wounded/killed/overkilled?
I can see situations where you'd still want to attack (wanting to kill the hero, sister of pleasure's heals, or if the attack dealt low damage) but it seems to penalize, if the attack is very successful.
4. Banished Heroes:
Do banished heroes return by resting? what happens if the spawn tile respawns to the board? what if the tile they roll to is full?
I find it doubtful they'd be removed from the game as easily as that.
Also two scenarios allow one player to control the respawns - how does that effect Banished Heroes?