Skysook,
I trust you've been to
link and seen the published requirements? These are what are being applied.
In accordance with HKG employment law and just like almost all other countries, work permits for foreigners won't be issued when sufficient local talent is available. As there is no industry (G/A, flying schools, regionals, etc) to 'feed' the airlines in HKG it's a vary rare thing for a HKID card holder to meet the DEFO experience requirements. Long story short: no, you don't need one.
Regarding experience, those who have been starting of late all have transport category aircraft / airline experience. Airbus experience is preferred but not required due shorter training requirements (read: saves time and money). It's not a job you go to from an aero club. If you aren't flying jets (either seat), multi-crew turbo props in airline ops (either seats) or biz jets (command) at this moment, you are unlikely to be successful.
Bongo,
A couple of interviewers are a little more tech-centric than the others but knowing company info (history, fleet, engine types, etc) your current type and AGK basics shouldn't be a challenge. By far and away, the majority of people come unstuck on the personal. They are unprepared for personal questions or speak off the cuff - disastrously - in response to personal questions they haven't considered.
The sim ride is stock-standard airline recruitment profile. Airborne, general handling, vectors for an ILS, go-around, some kind of failure (ie. engine failure), ILS and land. Raw data, hand flown. If you haven't flown an Airbus, get someone who has to talk to you about control inputs in normal law so you don't try and manhandle it around the sky. It becomes very easy....once you know how