Well Vicky, you got the ball rolling. I finally found David J (Joseph) McMillan's obit. He (David A. McMillan, son of David J.) does have a sister, Nancy. I think I found his (David J's) family (parents Peter Hugh McMillan and Catherine "Cassie" McDonald - 1st wife was Emma Wait) in Ontario, Canada, which would fit with my McMillan connection in eastern Ontario. Need to do more confirmation since I don't see a Nancy in the census records for this family.
Thanks for your help