So, party bus parks itself in front to Countdown. Countdown does the Ailerons thing, but can only really move forward about 2 millimeters, then reveals a 1-forward and still cannot move. How many times does APL trigger? Twice?

Yes. Ailerons is a while maneuver, dial reveal is a maneuver, so both times would threaten.

Twice. Once for AA, once for the dial maneuver. They're both maneuvers, each one is a separate opportunity for APL to trigger, and APL doesn't have a once-per-round limit.