a. I suppose Mr. Leung and Mr. Tung used Wade-Giles Romanization (or system)
for their name's spelling, which looks very popular outside China mainland
including Hong Kong, and inside China mainland before the year of 1958 when
Pinyin (Chinese phonetic alphabet) was published.
Wade-Giles is a romanization system for Mandarin, not Cantonese. The Yale romanization for Cantonese developed by Parker Po-fei Huang and the jyutping (粵拼) are more likely sources for Cantonese names which use a codified romanization system (jyutping being more recent). Many names use folk romanizations, rather than following a specific system.
regards,
Ted Hardie