TWOV questions - Does it qualify?

USA > Chongqing (4 days) > Beijing (5 days) > Tokyo (3 days) > USA

Direct flight from USA to Chongqing, train from Chongqing to Beijing. Three questions:

1. Does this itinerary qualify for the 240-hour visa free transit?
2. If so, does it still qualify if the stop in Tokyo is just a layover? So, say instead of staying there for 3 days, I only stay for 3 hours.
3. Anything else I should be mindful of?