There's a few things in the Shefford marriages books you're looking for. Nothing on Marie Josephine Senecal and Bernard Flanagan.
Francois Chenette, Vf Thoetiste Tetreau STUK 08-11-1859 to Dubreuil, Louise
Louise Dubreuil was the daughter of Augustin and Marie Jeanne Flaurant
Francois Chenette, Vf Louise Dubrauil ROCH 19-07-1867 to Tochette, Lucie
Lucie Touchette was the daughter of Andre and Louise Lacroix
There were at about the same date two other Chenette marriages to Dubreuils in the Shefford county books (1860, 1864) at ROCH. Their parents are both given as Francois Chenette and Marguerite Charron This may be the parents also of the Francois Chenette above with two
remarriages as a widower to Louise Dubreuil and Lucie Tochette.
One marriage is listed for a daughter of Francois and Louise Dubreuil
Delime, dau. of Francois Chenette and Louise Dubreuil WATE 21-02-1898 to Deslauriers, Clement
Vf in these records is "widower of." So the Shefford books only have records of two remarriages, not the original marriage. On a second marriage, the names of the parents are not given. But in this case you can probably safely "guess" the parents were the same as two other Chenettes married at about the same time in the same records.
I think the abbreviation ROCH stands for La Rouchelle (records begin in 1857). STUK stands for Stukely (1846).
The two other Chenette marriages I referred to above were:
Julienne Chenette, dau. of Francois Chenette and Marguerite Charron ROCH 09-01-1860 to Dubreuil, Olivier
Justin Chenette, son of Francois Chenette and Marguerite Charron ROCH 06-06-1864 to Dubreuille, Louis