you are going to have a pain in the ass time to prove to the US you are capable of practicing medcine in the states, that is if you are tryint to.I was considering a similar idea early in the app cycle, then decided against it. For one, I wanted to go to Taiwan for med school, but they have a different med program. After high school, it's straight 7 years, so they'll look at high school transcript and all. Instruction in classes are in Chinese/English. But I think it's much more difficult to come back to the states with a foreign degree, especially for residency and afterwards.
Idk much about HK, but it should be similar.
Best to stick to the states if that's where you plan to live and work.