2. The possibility of applying is very high, because except HKU, HKUST and CUHK, it is not difficult to apply for teaching-oriented master's degree in other schools, and you can apply for multiple schools at the same time.
3. It doesn't matter which intermediary is good, and DIY is not a problem. After all, all schools in official website have detailed application procedures.
4. It is useful to apply for GMAT in City University of Hong Kong, because it is clear that GMAT is helpful for admission. But other universities are not necessarily useful, and it is hard to say exactly. Generally speaking, there should be no problem if you don't take the exam It is suggested to go to these three schools in official website to see the professional introduction and application requirements, and consider applying for a master's degree in finance.