I have Catherine MacMillan b Isle of Muck married Neil MacKinnon, born Isle of Muck in my husband's family tree. Catherine is a daughter of Lauchlin MacMillan b Isle of Muck and Catherine Campbell b Tiree, Scotland. The families settled Lake Ainslie abt 1822. Catherine had 7 brothers who along with the widowed mother settled in Cape Breton.
I have the family siblings for Neil and Catherine as you posted.
Neil "Tailor" MacKinnon married Annabel MacLennan b River Denys, NS
My husband is a descendant of Catherine MacMillan's brother, Duncan who married Julia Campbell abt 1812 Isle of Muck.
I believe this to be a connection.
Ethel