“In conservative Latin societies, if at the time of your birth your mom was not married to your dad, you got her last name as your own. Then, maybe you would use your dad’s last name as your second last name, or maybe your adoptive father’s (maybe mom’s new hubby). And if she divorced the new guy, you could change yours too if you liked the new guy better.
“So the 1912 Ramos could be the appropriate second last name at the time, and Baez the appropiate one thereafter, and maybe he found out by 1918 that his father’s last name had been Valle, and used that on official documents trying to accommodate U. S. usage.
“Of course, de la Caridad is his middle name; in the draft card someone put his last name in the middle name spot by mistake, something that would be repeated for decades by ballplayers, like Latigo Gutiérrez being known as René Valdez in the U. S.
“Your research on his mom, Marcelina [see below], looks pretty definite to me, so it is clear he used her last name as his. And I guess he pretty much preferred to use Baez as his second last name during the latter part of his career. Which he has a right to. So it is José de la Caridad Méndez Báez.
“However, you have just revealed the true mystery. Who was José’s father? I'll ask some Cuban historians (as I am not one) and let you know.....”
A few additional notes from Tito and from my own research:
• Tito also disposes of the version of Méndez’s full name given by Roberto González Echevarría in The Pride of Havana, “José de la Caridad Méndez Arco de Tejada.” There was, Tito says, a Cuban sportswriter “with a peculiar sense of humor, who gave ballplayers and famous people fanciful second last names based on Spanish noble names, usually compound last names. ‘Arco de Tejada’ is one such feeble attempt at humor; please disregard it.”
Incidentally, the longtime Pittsburgh Courier sportswriter and columnist, Wesley Rollo Wilson, had a very similar habit, often for example calling Judy Johnson (whose middle name was Julius) “Julius Caesar Johnson.”
• In a 1920 interview with the newspaper Diario de la Marina, the legendary slugger Julián Castillo refers to Méndez as “the celebrated Méndez-Colmenar del Valle.” Tito’s comment: “It could very well be. Some people with compound names preferred to simplify, and dropped half of it. So Jose could very well be named Colmenar del Valle and refer to himself as ‘del Valle’ or even simply Valle.”
• On Méndez’s mother: the World War I draft card for José del Valle Méndez lists his nearest relative as “Marcelina del Valle,” of 38 Factoria, Habana, Cuba. Marcelina was Méndez’s mother’s first name, and her address in 1917 was 38 Factoria in Havana. Here is what’s entered as Méndez’s relative or friend in Cuba on passenger lists in the 1910s:
May 7, 1914: “mother Marcelina Lugones”
April 22, 1916: “mother Marcelina Méndez” (Méndez crossed out,
actually traveled the next day)
April 23, 1916: “mother Marcelina Menendez [sic]”
May 9, 1917: “mother M. Mendez Lugore [sic], Factoria 38” (same
address she is given on Méndez’s draft card)
May 13, 1917: “mother M. Lugones, Factoria 38”
The image of Méndez above was snagged from somewhere on the internet (I’m forgetting where at the moment), but it is originally a detail from a team photo of the 1920 Kansas City Monarchs.