Thank you for your earlier advice! We really appreciated it!

Yes, we are aware that Jetstar is not Oneworld, so no OW benefits but booking 'Max' fare will at least give us some flexibility with our checked bags and stuff. I guess the lounge access is a bonus (which seems pretty basic from what I have researched). I've purchased our tickets using my AMEX Gold Card which I believe has travel insurance so hopefully, that covers the trip with regards to Mount Agung. I will also be getting travel insurance through our banks. And if worse comes to worse and if Jetstar will offer rebooking, the we have other destinations in SE Asia as a back up (Phuket or Malaysia comes to mind but hopefully not!)