Oh My! Forget Bolton, Ontario, really! The Family History Library catalog points to a roll of microfilm "FHL US/CAN Film 1031527" of parish registers, 1851-1876, from three neighboring parishes. This is available at local Family History Centers.
Quebec, Brome, Saint-Étienne-de-Bolton - Church records
Quebec, Brome, Bolton-Ouest - Church records
Quebec, Shefford, Stukely-Sud - Church records
That film may be your best bet for finding the births of Victor and Job/Joseph and the parents' names. The American-French Genealogical Society (AFGS) in Woonsocket, R.I. has printed dictionaries of local Catholic and Protestant church records, including births and marriages of "N-D-Bonsecours" in Stukely South/Sud, Shefford County. They also have the Drouin film which should include the parish records.http://www.afgs.org/
A careful study of the Loiselle Index and the Blue Drouin should help. The AFGS has microfilm of these on loan. If these contain the names you seek beginning with Pierre and his spouse, the Drouin, in particular when combined with the Red Drouin, should give you the ascendency to the pioneers as a road map to finding the relevant primary records on film. The Drouin can help identify any possibility of dual couples with the same names.
By the way, I just noticed the mention of Bolton, Quebec in your Poulin/Dumas thread of last July.