My trip is from LAX to BKK with a transfer in Beijing Capital Airport (with Air China).

1. Generally, it needs at least 1.5 hours to transfer for a international flight. If you arrive and departure in the same terminal and no baggage checking is needed, then 1h20min may be enough.

2. It depends on if you have a connecting flight. If it is, they will check through for you. However, it is better for you to verify with your air company.