I recently purchased nwa tickets for my parents, SFO-NRT-BKK-SGN-PUS-NRT-SFO, with BKK-SGN segment operated by Thai Airways and SGN-PUS segment operated by Vietnam Airlines. In addition, they will have a forced overnight in BKK. So, here are some of my questions:

1. Will nwa provide accommodation in BKK because of a forced overnight? (I called PE line and was told that nwa will not provide food and accommodation since the last segment is not operated by nwa, despites the fact that I purchased the tickets directly with nwa.)
2. Can my parents be able to check their luggage all the way to their final destination, SGN? (The PE line said yes, nwa has an agreement with both Thai Airways and Vietnam Airlines.)
3. Will my parents have to pay international airport taxes @ BKK because they stay overnight in BKK? (I forgot to ask the PE line this question.)

Thanks for your assistance.