After some fascinating rabbit holes, my colleague Elsie Wilson and I offer the following theory:
James Flynn m Johanna McCabe in about 1883 in the Little Wolf, WI area. He was a very early settler up there.
They had 11 children, one of whom was Magdeline Flynn b.1898.
Magdeline marries Oliver Guerin b.1890, natural son of Leroy James and Armenia Bruley, in about 1915. Their first child was Vivian Flynn Cebrowski being born in 1916, then Nona Flynn Bagin b. 1919.
At about the same time, James Flynn dies and we find Johanna has remarried to Joseph Potter Guerin by the 1920 census and they have Vivian and sister Nona living with them as they were Johanna's grandkids. Later, in Regina Flynn Reetz's obit, Joe was referred to as a foster father. This leads me tho think about a significant family disruption in about 1920
As an aside, the image of the 1905 Little Wolf census makes it clear how the Guerins Flynns Kosmershocks, and St Georges knew each other--they all lived within one census page of each other.
Oliver's 1917 draft card has him and his family renting in Hevetia, Wisconsin and here's where the speculation starts: The original poster mentioned a family last name of STONE. Common enough name, but there is a Harlan Stone b 1865 in Helvetia in the 1905 and 1910 Census'. Could Oliver and Magdeline have known them or rented from them? That might explain "old family stories" that youngsters incorrectly remember and oldsters tell.
I can't find a trace of Magdeline Guerin after 1920 so it's led me to wonder if she and Oliver died together leaving the children with Joe and Johanna Guerin?
I don't see Joanna after the 1940 census, when did she die?
One thing I was wrong about in my first note was that Roy E Guerin and Leroy E Guerin are the same person...bad data.
I am looking for Waupaca Guerin descendants and information and will be in the area in August 2013 for a reunion. Do not hesitate to email at firstname.lastname@example.org