(1) Is there a reason you aren't applying to PhD Finance or PhD Financial Economics programs? Remember that finance at the PhD level is *very* similar to economics. "Finance" as a research discipline is basically financial economics, and is much more rigorous than undergrad finance. In my opinion, someone with your background should always aim for PhD finance - better funding, better chances in admissions, similar research/tools. The only exception is those students who want to do micro theory.
(2) I'm aware that your pedigree is pretty strong, but I don't think American adcoms will accurately recognize the strength of a finance degree from HK. Lack of econ faculty connections from your letter-writers will also make it more difficult. If you want to apply to PhD econ programs, I strongly suggest getting an econ master's in Europe first. (possibly UK or Canada)