I have a Stephen James McKechney (born June 9,1885) listed on the 1901 Census for Arran,Bruce North, Ontario. He is the son of James and Cristena McKechney. The other children were Ella M., Duncan H., John G., Evyln C. and Emma R. The surnames often varied from census to census depending on how the census taker decided to spell them. James and Cristena are listed as McKechnie on the 1881 Census. On your posting you mentioned Duncan and Jack, it is possible that John went by the name Jack, as did my grandfather.
James' parents were Stephen McKechnie and Margaret Duncan, both born in Scotland. Their other children were John, Thomas, William, Elizabeth (my ggrandmother), Mary and Rachel. I have their years of birth and a little more info on Stephen and Margaret. If you think that this may be the family you are looking for I would be glad to share the info with you.