I am Euphemia's ggggranddaughter through her daughter Sarah. Unfortunately I think you have combined 2 families into one. Alexander and Euphemia Stewart, both born in Ireland, had 5 children, Mary Ann, Andrew, Ellen/Eleanor, Sarah, and Alexander. It looks to me like John Calvin, Margaret and Elizabeth are the children of another Euphemia and Alexander Stewart who are from Scotland and about 20 years younger. I do have some information on the ones from Ireland if you are interested.