Hi Dan,
I have some obits if you want to reply to my email I can scan them to you. The other son Arnold Edwin died in Victoria in 1987. John Emil was married twice first to Kathleen Wheeler in Nelson in 1936. There appears to be no death for her so they may have divorced. I did find your McMillan family in North Dakota in 1900 but no other sign of them or their marriage or birth of their children in Ontario.
jumawa@shaw.ca