Personal safety is seriously not an issue in any district.
Assuming you are accepted in the EdB NET scheme - specially the secondary one - the issue to watch for will not be the district, but the band of the school. Band 1 having generally the most academically able students, with Band 3 at the bottom. Even so, as an experienced teacher you will already be aware that the principal and the school board set the tone of the school a lot more than the type of students.
The other thing to consider in moving to Hong Kong is that you can't afford to be too fussy about the first job you accept; you need to establish local street-cred so to speak. It's an employers' market here, so if you can show you've got the goods by handling a less desirable position in your first year, it will be very helpful for getting you a better post subsequently.
And don't restrict your horizon to the EdB NET scheme - there are also some DSS (direct subsidy) schools which also offer competitive packages. There are also a few international schools which employ specialist NETs - they're not the "top of the tree" ones, but they do pay a living wage while you find your feet here.