Thanks for the link - it mentions the magazine article I clumsily cited: "Also [in] the 'Cape Breton's Magazine['], # 28, George Maxwell of Sydney tells
stories of his family. He was the s/o George Maxwell (the twin) and grandson
of George Maxwell, who came to Judique as a small boy with O'Hanley."

So the story of the twins that I remembered reading was, apparently, not the story of the George Maxwell (younger) who was being interviewed, but a story he was telling about his father and uncle. I think I've got it now ... (!)