I think you need to look hard at this one. Those 12 hour flights are a back breaker in Y and I would certainly be looking to my company for J in these circumstances. I have no idea what your company policy is, but with a career move I would not be looking to start out down the back - it may depend on who instigated the move?
Also bear in mind that assuming you will get home leave flights, you will most likely receive the same sort of flights, and doing them for the foreseeable....
I would start negotiating and be prepared to offer alternatives if you have to - ex - EU etc.
You need to think about housing allowances as housing costs are enormous, and also schools for the kids, there are waiting lists for most decent schools, and some are closed unless you have siblings already there!
With kids think about where you want to live, where I lived our kids played rugby, football etc but was an expat community on Lantau - great for the airport, but a bit longer onto the island.
Good luck and negotiate hard - I did