1. Chagos is the group of islands in the Indian Ocean where Diego Garcia (and the US Air Force base) is. I didn't know, though, that it was open to commercial traffic

2. Yes, RT award for 20k in Y for South/Central Asia. That is one of the better use of US Miles for *A awards out there!

3. As Singapore is next to Malaysia (mentioned), I'd say that SIN is in the South/Central Asia zone too. So is BKK (Thailand mentioned).