@ossobuco,
You made me look (after the model of the Angel). And it was not a legend!
(For us kids it was kind of kinky to think as somebody's granny posing nekkid!)
The model was Alicia Rivas Mercado, the oldest daughter of the architect Antonio Rivas Mercado, and the president of the foundation that bears the architect's name has the same last names as my grade school-mate, so she must be his sister.
Nothing is publicly known about Alicia's life (her daughter married a Mr. Gargollo, I can tell, for my schoolmate's last names were Gargollo Rivas). Her sister Antonieta was much more famous. A writer and pioneer of feminism in Mexico, who died tragically in Paris, at age 31.
As for the model of Diana, I know a lot about her, but will not go on gossiping online about my neighbors!