The trip is over.
Crew and service on JQ44 DPS-MEL in Jetstar business class were as nice as ever. A premium economy-like experience rather than true business class. There's just one meal service on the DPS flights. There's two meals on the longer SE-Asia flights (eg to SIN). They hand out a second menu.
JQ44 landed nearly 2.5 hours late. Not at 21:15 but at 23:41.
Then, because the flight was from Indonesia, there's a bit of a delay while biosecurity staff come on board for an announcement and they set up disinfecting floor mats at the gate.
I had to think about the question the machines ask: Have you been to Indonesia? I answered "no" but informed customs of my exact situation - i.e. that I had done an air-side transit at DPS. I was waved through.
Summary:
It all went pretty much has I had hoped. I could stay air-side the whole trip. Even with checked luggage, I think you could stay air-side. The Jetstar transfer desk in SIN did ask - I think they could have transferred checked bags.
I did get access to the F-lounges in KUL and SIN. I did get all daytime (well, not overnight) flights.
The worst part was JQ44 being so late. As far as I'm concerned, the least time in Bali airport, the better. And that the promised 3K inflight meal deal voucher was not loaded. Oh well.
The best part was that I was home by 00:35, despite JQ44 being so late. Soon after in bed.
And today I don't feel jet-lagged at all!