I found Joseph and Euphrosine in the 1851 census and they have a son Solomon who matches the age for the one who married M Anne's sister.
They also have several other kids that will keep me busy for a while tracing, as well as three kids surnamed Poirier living in the household.Since these kids overlap the Lanctot kids, I suspect that they are nieces and nephews.Any information people have on any of these (and their descendants), especially the Poirier connection, would be appreciated.
Province: Canada East (Quebec) District: Huntingdon County District Number: 10 Sub-District: St Constant Sub-District Number: 138 Page: 55 Line: 19 Roll: C_1120 Schedule: A
Joseph Lanctot55 St Constant cultivateur Eufrozine Hall45 St Constant Celanire Lanctot (f) 17 St Constant Ismael Lanctot15 St Constant Solomon Lanctot12 St Constant Philomene Poirier13 St Constant Helene Lanctot10 St Constant Samuel Lanctot6 St Constant Venray Lanctot (f)4 St Constant(may be Vernay or Penray) Horace Poirier4 St Constant Benjamin Poirier2 St Constant Marie Lanctot32 St Constant
living adjacent: Sofime Lachapelle24 St Constant journalier Lena Lanctot26 St Constant Donald Lachapelle7m St Constant
In 1861 there are all of the Lanctot kids except Celanire and Helene who might be married by then, and two Poirier kids: Philomene now 22, and a 10 year old Moyse Poirier.
The only Rootsweb tree that has the couple only mentions a Celanise who appears to match Celanire, who married a Vital Monchamp.There is another tree with the names misspelled that appears to trace Samuel, who married a Mary Menard and moved to Vermont.