Bernadette~
I have always wondered what connection Angus Munn had with the Cannon family and thanks to your post I have figured it out!
The Leanora Callister that married Angus Munn (McMunn) is the aunt of my 4th great grandmother of the same name (Leanora Callister) that married Captain George Cannon. The name Angus Munn is carried down through many generations in the Cannon family. Angus Munn Cannon is the son of Captain George Cannon.
I am not sure which John Cannon you are inquiring about, but I have a John Cannon born 4 Feb 1728/29 in Cooilshellagh, Kirk Michael, IOM. He married a Jane Kelly 9 Aug 1766. He is the Uncle of my Captain George Cannon who I am doing research on right now.
Let me know if any of this sounds familiar.
Leslie