I'll try to answer your questions as best I can:
1. Latest price of Wii Japan version
About HKD2500.
2. Latest Price of Wii US version
About HKD3000.
3. Which is the official version of Wii in HK? I don't think US / Jap versions are the official versions.
Not officially sold here so there is no HK version.
4. Price of getting a Wii Chip Modded
About HKD300.
5. Wii Japan version chip modded = Wii US version chip modded?
I believe that they use the Wiikey chip. Once modded both will be able to play copied/backup games as well as the originals.
6. Are shops selling Japanese Wii games or US Version Wii games more?
Not sure as they are so expensive I've stopped looking.
7. Why do people buy Japanese versions in HK? I would expect HK people being able to read more English than Japanese...
They buy the Japanese versions because they are cheap (both the console and the people

).
A word of warning and that is the Japanese version is known to hang when trying to play certain English games. The same game will play fine in a US version Wii.