Rated 5 out of 5 stars
An excellent job. The addon is extremely useful both for novice and for native speakers (there are many words in the language that I don't know how to pronounce properly).
For future enhancement, think about adding audio pronunciation, like clicking a button in the popup window to activate an audio file. This would help those who may have difficulty distinguishing between, e.g., "pa1", "pa2" or "pa6". Such a feature is available in the web site http://humanum.arts.cuhk.edu.hk/Lexis/Canton2/.
It may take some effort to make this wish a reality. In the meantime, a poor man's version (this feature itself has its own uses) is to list 4 or 5 other characters that have the same sound.