Dan Winterland is right move Biz Jets and LCC's to Macau and Zuhai once the bridge is done.
This can be done with "pricing signals" reflecting the amount of time a Global Express or G IV takes on the runway - which is longer than a 744 due wake turbulence category. After all, in Europe, O'Leary Air and Stelios Jet go to secondary airports like Frankfurt Hahn and Rome Caimpino.
If you are an F/O or S/O with a HKG carrier you need that 3rd RWY inside the HKG SAR if you want your command! Anything outside the SAR is not covered by HKG air services agreements and won't be available to HKG airlines.
WRT to airspace - maybe we are looking at it back to front. the PRD from ZGGG to HKG and around seems to have virtually no military airspace so for better co-ordination of PRD airports maybe HKCAD can subcontract approach and area control to ZGGG FIR and just have tower run by HKCAD (similar to the arrangement VMMC has now). Then maybe we could cross SIERA at 4000' on left base for 07L? Like to keep feet rather than metres somehow tho.....
Just sayn'