What a coincidence - I have just been going thru the St. Polycarpe church registers, so your mention of Toussaint caught my attention. I went to the "big book" that Bob D'Aoust has painstakingly researched and found 3 Toussaint/Tousseint names.
You will have to eliminate this guy - Tousseint (son of Etienne and Josephte Judith Roy/Roi) - b. 1847 (too young to be married in 1858).
Toussaint #2 was the son of a D'Aoust daughter (Ursule - she is the sister of the following Toussaint), so his last name is Valade, plus he was born in 1863.
The other Toussaint is the son ofAlexis and Josephte Calve. He married Justine Faleque Felx dit Faxe on 19 Feb. 1833 in Saint Michel de Vadreuil, Montreal. The book lists only 4 children, born from about 1841 to abt. 1844. There are no other children listed. (The fact that there are no dates for these births means that they never were discovered in all the years of research. In those cases, Bob has guesstimated birth years from the average ages of young men and women at the time of their marriages.) With only 4 kids listed, it could mean that his wife died fairly early into the marriage, which would leave him looking for a wife. I know that this would be a 25-year gap between his 1st marriage and this marriage. But the marriage entry in St. Polycarpe does have him marrying a widow, so if Toussaint was also widowed, it would be a perfect match. I cannot remember if the marriage entry gives the names of any witnesses, which may or may not give some family "hints".
Sorry that I cannot give you a definitive answer - just my speculation.