There's no way you're making the CX flight.

More generally, does FD even stamp a domestic BP as international to allow pax to get through immigration in HKT? You'd need a int connection to do this and I doubt FD would/can process it.

If someone can shed light on this...... but until then I'm of the belief that you'll never be able to get through immigration in HKT in this scenario, even with a 'legal' connection.