I think I can rely on my grandmother's testimony about her own father being from France.
I suppose I could just tell my grandmother that she's making it all up and doesn't know her own father.
I can accept that many Alderete's are from Durango,Mexico, but not all. I can accept that Alderet is a derviative of a Basque name, too.
To suggest that it is unlikely for any european Alderete's to have immigrated is a very small box that I can't force reality into. And the Basques--though a very old people-- were not immune to Spanish history (Romans, Visigoths and Moors).
I myself am a Chicano--from America-- and my wife is from New Zealand, in the South Pacific. I know firsthand that families don't always happen in straight lines.
But I'll keep my mind open to anything reasonable, but not anything "all-or-nothing".