I have sent you some details off list but I believe Placida's maiden name was CHAVES.
I found this out on an ancestry.co.uk search of the personal family trees. If you have access to ancestry.com you should also be able to see this information if you lookup the LARGE Family tree. Or, do a search on Jesus ARAGON and look in the Family Trees filter. You should then find what I found and have the details you require.
I think Placida's parents names were Ignacio CHAVES and Gertrudis CHAVES.
Jesus ARAGON's parents are Juan Agustin ARAGON and Ana Maria SENA.
It looks like Jesus was married previously. This info' is on the email I sent you.
Hope some of that helps.