Did you ever figure out what happened with "Y, Somme, Picardie, France"?
I did and I shared that a year or so ago on more than one other thread, but I don't know if you ever saw any of it. I think you'll find it pretty easily if you search specifically for "The Secret of Y, Somme, Picardie, France".
Your theory is more elegant and sounds entirely logical, but if you don't mind my saying so, you've been over-thinking it.
In a nutshell, the misinformation originates on various Members' Family Trees due to a specific data entry mistake that I've explained on a small blog (link below), focused solely on the "Y, Somme, Picardie, France" phenomenon. Here's the link: http://ysommepicardiefrance.blogspot.com/