Thank you for everyone's suggestion and I will definitely find more information on those areas. I had the strategy to look for school first, then housing, but the situation has become kind of hopeless for me (after calling about 100 schools (international, Chinese, English, subsidized, private in Island, Discovery bay,hong kong island, kowloon and still can't find two spots for my kids, I did not call the ones that are very far away from CWB). Most schools don't have spaces. Some Chinese school still have space, but they say my daughters have to take Chinese entrance tests and pass in order to enter (my daughters are fluent in speaking both Cantonese and Mandarin, but not in writing Chinese), a couple of schools would not accept my Primary 1 daughter because she is a couple of months younger than their age requirement (and I don't want my daughter be downgraded and repeat kindergarten because she was tested to have 2nd grade reading level when she was in kindergarten, and she very tall and mature for her age, I just don't want her to be "king" of her class and not learning much if she is downgraded to kindergarten). Right now there are two local schools that have space and are willing to accept her if my daughter passes the interviews when we arrive hong kong next month. But I recently found out those are the worst schools not only in their district, but also ones the worst in whole Hong Kong. And I am not sure if I want to send them there.
So, I guess if the worst happens that we need the government place them to not our choice schools (at least they say they guarantee our kids will be placed in schools in our living area district) and both of my kids are downgraded to kindergarten and 2nd grade, at least I hope we will live in a place that we like.
If school situation eventually does not work out, I may just homeschool them (I read an article that it is not totally illegal in Hong Kong). We are still excited about our new journey in Hong Kong, Cheers!!!