Hello Fiona- Found these obits. Might be your Michael & Edna St. John. Don't see any daughters listed, but there might be something here to help you out.
Feb 7, 1958 Edna St. John of Northlake, beloved wife of Michael; loving sister of Lillian Munk, Walter and Clarence Boldt, Mabel Botts, and Anna Hartman. Funeral Friday, 1 P.M. at funeral home 140 E. North Ave., Northlake, Ill. Interment Concordia Cemetery. Fillmore 5-5075.
March 18, 1973 Michael St. John of Northlake. Funeral services Monday March 19 at the Northlake Funeral Home, 140 E. North Ave., Northlake, Ill. Interment Concordia (Cemetery). Visitation after 2 P.M. Sunday. 562-0044