RE: Indonesia, volcanos and winds
Indonesia is roughly 2,900 nm in length, so two events occuring "in Indonesia" may be as far apart as London and Riyadh (or Miami, FL and Vancouver, BC).
The Merapi volcano (of recent news interest) is about 800 nm SE of the Indonesian island on which engine debris fell.
The SE trade winds in that latitude do flow from the volcano in the general direction of Singapore and the location of the engine failure. Whether it was a factor (IMHO, no) will be fairly easy to determine by looking at all 4 engines for tell-tale glassy residue, etc.