With kids have you thought about a stop over for a couple of days in LA? We did & was so glad we did it, not only because it's too far away to get to Disney now but the time difference between LA & NZ seem to help the jet lag & adjust to the time, also it's a free stop over so just paid for the hotel & park for 2 days, although there were only 3 of us then :-) Still managed to leave the car seat at the airport, amazingly they found it on our return very easily.
My in laws & brother have used the showers in HK & said they were great, everything provided as far as I know & great to feel refreshed after a long flight