If I have no won story card and then manage to win two at once, one of which is The Well, do I:

always have to return the other won story, or

never get to return any story card in this scenario, or

somehow get to choose one of the above according to the situation in the game, since I'm the active player?

And what's the governing rule for such situations, i.e. something affected happening at the same time with a card affecting it?

Similarly, if a numerous number of characters with comes-into-play abilities is revived via The Secret of the North Wood, how are such abilities resolved?

My guess is first the active player gets to choose the order of abilities of their characters, then the next player to take the turn does the same, etc.

Thanks in advance for explanations.

As the active player, you get to resolve the order that stories resolve. Also, you get to choose whether or not you trigger the win effect on a story. So if you win The Well, you can choose not to trigger it.

What effect lets you win two or more stories at once?

My bad. Stories are not resolved simultaneously so they can't be won simultaneously. A lesson learned.

Was at least my second assumption about The Secret of the North Wood scenario correct?

charmer said:

(v1.11) Simultaneous Effects
When card effects, passive abilities,
or forced responses would resolve
simultaneously, all cards that are affected
resolve in the order determined by the
active player, one at a time. The player
must fully resolve each effect before the
next effect takes place.
Whenever character or support cards
enter or leave play at the same time, the
controlling player chooses the order in
which they enter or leave play.