Well, that should have been obvious. Willie Mulvaney was named after his mother Julia's brother William Toner. Or something like that. Probably. Maybe. Could have been. William was a common name, after all. Is a common name, after all.
I don't know why, but yesterday the dates hit me.
William Toner died January 31, 1899.
Willie Mulvaney's birth is various given as 1899, 1900, 1902, 1900, etc. The first recorded birthdate for him, though, on the 1900 census, is 08/1899. Given that it was recorded mere months after the supposed birthdate, I'm inclined to trust it as more reliable than the rest.
If it is accurate, Willie was born a mere 7 months after William died. Julia was already pregnant with her son when her brother died.
Any doubt I may have had about the provenance of Willie's name is pretty much gone now. I'd love to be able to conduct similar analysis of other ancestral names.
(Some of them are obvious. The eldest Mulvaney son was James, likely named for his paternal grandfather, Patrick's father James Mulvaney. Auntie Mae - Mary - was probably after her maternal grandmother, Mary Cullen Toner. Or the Blessed Virgin. Or both. Thomas for his paternal uncle, Patrick's brother Thomas. But Veronica? Raymond? and what does the J. in J. Harold Mulvaney stand for? (you haven't seen that yet. I got a scanner, so it's coming, I promise.))