Put me down for the same. I hope to fly back to HK for New Year's celebrations, but I could be flexible.
As for not diving afternoon of 29th - I'm reasonably sure that low-altitude flight + 12 hour break should be more than enough...ergo you can dive in the PM if you want.
PADI's 24 hour rule (I believe) is based on double the accepted minimum of 12 hours, and that in turn is based on an international flight at 30-40,000 feet, rather than the 8-10,000 feet we might manage...
...anyone more knowledgable out there?
OTOH spelunking sounds dirty and fun.
Cheers,