My Michael & Bridget Coughlin Mahony & family lived on West Side in Oswego. There were many Mahony's in Oswego; still checking.An older relative said many went by Mahony or Mahaney/but name is actually Mahony. Have not found relationship to your John & Ellen Mahaney.However,I know that their son, your Michael the painter, lived on the East Side, Hamilton St. Think I remember reading something about your Daniel the florist.Great site to try is www.fultonhistory.com.
Tom has scanned many old newspapers on this site, many Oswego.I've had great success. If you get into the newspaper archives; type in any of your names or variations of names, dates, etc. exact searches, boolean, etc. You never know what you may find in obits, weddings, visits, etc. to lead to other names.