Carranza crashed in the New Jersey Pine Barrens on July 12th, and every year, there is I ceremony on the spot, which is in the Wharton State Forest, near Tabernacle, New Jersey. This year, the Memorial is on July 8, at 1pm, I believe that his is the number to call for more information--609-567-5907.
One of my guitar students from long ago, grew up near there, and told me that, at least at one time, the ceremony, which centers on the laying of a wreath, included music and singing, and was a very important activity for the Mexican-Americans in the area.
I am told that the event is sponsored by the Mt. Holly American Legion, and is chaired by a fellow named Bill Nee. The number above is probably his (I got it from Wharton State Forest Information). I understand that it is coordinated with some activities in Mexico--so, if he doesn't have information on the song, he can probably put you in touch with someone who does--They still love to sing and play music in Mexico--
Anyway, good luck, and please, if you get any information off line, post it here--