Hi again Albatross. You have several considerations here -- job awfulness, cost of living, cost of future kids,etc. Rather than get bogged down and possibly paralyzed by considering all of them simultaneously, maybe you should pick one to address now, and then let things shake out from that first change. See what develops. Even though as mustachians we are master planners, sometimes it's best to jump feet first into one change to get things started. You might be surprised what develops. And easier to do now when you are young and life is relatively uncomplicated.
For example -- get another job now in Hong Kong. Or -- leave HK and go to New Zealand, if you're pretty sure that's where you want to be long term.
Life is short. Certainly too short to be miserable.
Good luck!