I am not related to those people but I like genealogical challenges.
I believe that I have been able to reconstitute the Latulippe families but the Ancestry of William (could go by theFrench equivalent of Guillaume also.) is more difficult to establish because of the absence of other Gagnon in his entourage (e.g. Gagnon godparents for his children).
Latulippe: Desiline Addie was the daughter of Jean-Baptiste (JB) Latulippe and Martine Rodrigue.Parents were married on 25 Sep 1849 in Beauceville, Québec, parish St-Francois d'Assise.THis is located between QuebecCity and the Maine border.
I believe that Stephen, witness ofWilliam at his marriage was the brother of Desiline.Same for Louis, born in 1850.
Caroline Dubord was the daughter of Edouard Duford and Marie Desange Latulippe.The parents were married on 13 Jan 1846 in Beauceville.Caroline was the cousin of Sesiline (Addie). As grand parents, Desiline and Caroline had: Joseph Latulippe and Marie Louise Rancourt, married 16 Jan 1810 in St-Francois de Beauce.Joseph had a previous marriage to Marguerite Dion.
It is generally possible to ascertain the ancestry of someone via the godparents of their children.In the case of the children of William and Desiline, none of the godparents are Gagnon.
Those Latulippe were all related.There is no sufficient info to determine as to whether William also came from the same town or area as the Latulippe.
Unfortunately, there is in Quebec no province-wide registry of children after 1799.However, we have a database made of the Québec parish registries.Given that William got married in 1871, probably about the age of 21 to 25, I have found a William Gagnon, born in Dec 1848 in St-Chrysostome, between Monreal and the upper NY state border.Parents name were: John Gagnon and Elizabeth ?Dugue or Dugre.I have not been able to find the marriage record for this couple on account of the uncertain surname of Elizabeth.The godfather appears to be a brother or the father of Elizabeth. THe godmother's surname still has to be decipered.Godparents were generally a couple.
I will continue my search and will keep you posted.If you have any info on the presence of relatives of William in his entourage (other than his own children), that would help.