I really have no idea what I did wrong along the way. But, everything is working now, tks!
I did also run webupdate + mygarmin after place your file in the folder. ( no update shown )
Now UI display in Japanese and Chinese without issue.

For sake of it, I then deleted the Japanese text file off my nuvi and follow with webupdate. Strangly, webupdate did not show that I can update Japanese text file. ( I believed I might have mess up the garmindevice.xml file? )