Hi Rick, as "good2cu" said, ours is Samuel Mansfield Bay (actually from 1811-1849). good2cu, thanks so so so much for that information about Tomas Bay! I was trying to figure it out for a long time, because I saw he had many children and crossed the border with different wives, now I know why =)
The Alejo you mention (your grandfather's half-brother) was my great-grandfather. http://en.wikipedia.org/wiki/Alejo_Bay
The Alejo you shared on Twitter, is my cousin (great-grandson of your grandfather's half-brother Alejo).
I don't know a lot about the Cordell's, but I can tell you with a lot of confidence that Samuel Bay's parents were Thomas Bay (1779 - 1836) and Harriet Mansfield. I know a lot more of the line, and I'd be happy to share it. With the help of Tom (not our relative, but has kindly helped me trace the line) I have gone all the way back to our ancestors from France.
I would love knowing more about Tomas. I know he was a confederate soldier, but would like to know why/how/when he went to Mexico. That decision plays a big deal in my life =)