I'm going to disagree with most people above about the cost of living and savings.
Just last week I saw a brand new apartment for rent next to Long Ping MTR station (Next to Yuen Long) for 12500 HKD for 480 sq.ft. You can get 700 sq.ft. village house further out for 10k. These are all negotiable of course.
As stated above. Tax will be in the hundreds per year, not thousands. You will have to put 1500 per month into the MPF scheme though.
As for basic food and living costs, 10k should be enough if you eat at home and cook with ingredients readily available locally.
The big, big (and a few more bigs) cost will be schooling. You'd really have to research what you actually want in this area as costs vary dramatically.