My GG-grandfather was William Joseph Copp, (b Oct. 05, 1826 England, immigrated 1828, d. Dec. 24, 1917) who married Julia O'Shea (b. June 9, 1830).I am descended from their daughter, Elizabeth Jane Copp (b. May 26, 1862) who married Charlie Alexander Major on Oct. 18,1892.Charles David Major, their son, immigrated to Massachusetts and ultimately became my grandfather.
As far as I can tell from the Canadian census records, Elizabeth had several siblings: Cathrine(abt 1859), Henry (abt 1860)Jerimiah (abt 1865), John (abt 1867) William (?) and Maggie or Mary, (Jan. 31, 1871).
Looks like that Jerimiah is the one you are looking for.I wish I had more to give you, but I can only take the O'Shea side back one more generation, and it's pure guess work.
It looks like Julia's parents were Jerimiah and Cathrine O'Shea just from the proximity of the families --next door to each other--the ages seem to be in the right range, and the names are repeated.
As far as the Copp side I am at a dead end, but now with your reference to Devon I might be in luck.
Hope this is helpful, please feel free to contact me if you want to share information or have any questions.I am also in New England (Maine).