Thanks for sharing that link. There’s some great information there, particularly concerning the true identity of the actress in question. As for why a woman was cast in the role, one of the posters in that forum conjectures:
“It is interesting that they chose a woman for the role originally. I guess they really wanted the Emperor to appear weak and vulnerable by using a slender old lady.”
Perhaps… But I’m not convinced. A slender, old man could have been cast if the only criterion was to make the emperor seem weak and vulnerable. I suspect there is another reason why they chose a woman, and am still curious about it after all this time.