The reference to Canada in the 1850 census for his birthplace may have referred to what we now know as Ontario or Quebec, as Canada wasn't formed - or named until 1867. I assume you have that and the 1860 Census, and just haven't got around to adding them to the biography?
You may not have found the 1880 Census, as his name is misspelled Sirus, but it clearly indicates his parents were born in Connecticut ("United States Census, 1880," database with images, FamilySearch(https://familysearch.org/ark:/61903/1:1:MZFN-XQM
: 13 September 2017), Sirus Flint, Brasher, St Lawrence, New York, United States; citing enumeration district ED 196, sheet 103B, NARA microfilm publication T9 (Washington D.C.: National Archives and Records Administration, n.d.), roll 0925; FHL microfilm 1,254,925.)
I'm descended from some Vermont-Massachusetts Emersons and have some info that will help with his wives. Do you prefer that I share my information with you directly, or that I enter it in the WikiTree profiles?