Hi. I am Dorothy's brother. We had a sister Betty (Margret Elizabeth) who died in her early 20's. She was buried in one of the plots they had purchased for themselves. Their request was to be buried in the plot next to her. They also wanted their names inscribed on the reverse of her stone. Betty was married to Ray Miller. That should help.
Ida lives in Bluevale. If you want to get hold of her let me know and I will email her your email address if you get it to me. not sure how you do this on ancestry.ca. Bert Mitchell also has the mitchell family tree all mapped out but I believe it may be on ancestry.com