Last part of setup is fulfilling the "A1" side text of the quest card. I draw a card - it was treachery - it ordered me to increase my threat by for each hero not commited to the quest. Shall I:

A. rise my threat by 3?

B. Ignore the text, as heros cannot be commited to the qyest in the setup phase?

I think A)

The card should always provide some kind of hindrance to the Heroes. If you draw that at the start tough luck, at least the staging area will be clear when you start...

I agree, option A.