Do you only want to work in Hong Kong? If you do apply for ab initio and basically get the job without forking out loads of cash. If you want to be a pilot but don't care where, and are able to work without needing a visa in a country with a lot of aviation, still apply for CX ab initio but continue with your training.
The dilemma you have is for the wrong reason. If you want to fly in HKG only, then of course try for ab initio, with CX, KA and Gov. If you cant work overseas without needing a visa the dilemma will come if you don't get into an ab initio course and have to decide if it is worth throwing money at to try and improve your chances.