I'm afraid I'm still unclear on the the minimum required AP that heroes have to spend.
The FAQ says:
But a Hero must spend their AP until the first sector occupied by an Enemy Action Token has been reached, as explained to pg. 11 of the Rulebook
But the section of the rule book it references (which is on page 12 of Rulebook v4.1) states:
In any case, a hero must spend their AP until the first sector occupied by an enemy has been reached, or until their available AP have all been used.
The FAQ answer doesn't include that final "or" clause, and that clause seems pretty important to me..