This is a huge ask because all the markets in Asia vary so much from one to the other.
To understand all the ins-and-outs of foreign investing, taxation, dividends, regulations and market mechanics for Asia Pacific markets is a full time job - literally.
So much so that investment banks generally have full time teams of staff (not lawyers) that monitor regulations for any given market and advise the bank as a whole of any changes. Its a very specialised area to work in so there's probably only a handful of people in HK that could come up with all the info you're after. And unfortunately employment contracts would likely forbid them from using the information ouside their work domain and posting it on a website anyhow
