Hi there
Just been there with my family. Had 3 lens with me 35mm prime, 24-70mm, 10-22mm on a 1.6 crop body.
When attending theme park, must travel light otherwise the camera gear will wear you down. I have a 2 days ticket, so this is what I did:
Day 1 - 35mm and 10-22mm+tripod for portraiture and wide angle shots like fireworks.
Day 2 - 24-70mm for portraiture, general shots.
Summer is hot in HK, so don't bother with too much warm clothing. But remember to bring umbrella/rain coat, unless you want to buy and use pricey disney umbrellas (which are not too bad really...).
Have fun and enjoy!