Cape Breton and eastern Nova Scotia became home for much of the emigration from the Highlands and Hebrides but their music and song was Gaelic, not Scots. (as a language)
There's been several collections and studies made of these Gaelic songs, the most recent being Anne Landin's Guthan Priseil. (Precious Voices) An earlier one would be Fad Air Falbh As Innse Gall (Beyond The Hebrides) by Donald A. Fergusson.
The MacEdward Leach collection is on line here:
MacEdward Leach
If you explore this site you may find something of help as well:
Cape Breton Ceilidh
Mudcatter George Seto has a great collection on his website as well. He may pick up on this thread.