I have been in contact with Microsoft support regarding your questions and below is a transcript of the conversation I had with them today:
Mr: Hi
Lisa: Hello, thank you for contacting Xbox Customer Support. My name is Lisa. Please give me a moment to review your question.
Mr: ok
Lisa: There should be no problem using your hard drive on your new console, and your saved games should still be there also. You can use your Xbox Live account in Hong Kong however certain features would not be available and you wouldn't be able to purchase content off the market place, so we would advise that you consider setting up a new account.
Mr: So my games saves will still work?
Lisa: They should do, yes!
Mr: Should do?
Lisa: Sorry, I just wanted to double-check that for you.
Lisa: Your saved games will be fine.
Mr: ok thanks
Mr: What features will not be available?
Lisa: You would not be able to purchase content from the Xbox Live Marketplace.
Mr: From the HK marletplace?
Lisa: yes.
Mr: What about content I have already purchased. Will that still work?
Lisa: Sorry, I mean a lot of the features that were available in the UK marketplace would not be available form the HK market place. You more than likely wouldn't be able to use your downloaded content in HK either unfortunately.
Mr: So if I was to create an new HK account would my saves still work or would I have to start from afresh?
Lisa: If you are starting a new account, you would have to start from afresh unfortunately.
Lisa: Sorry about the inconvenience with this!
Mr: So I would also have to choose a new Gamertag
Lisa: yes.
Mr: Well you have been a great help Lisa
Lisa: Thank you, I hope you enjoy your time in Hong Kong. It was good chatting with you today!
I hope this helps answer some of your questions.
