Unfortunately, the Duffys do not appear to have registered birth, marriages and deaths civilly. I can't locate a civil marriage record or a death record for Kate. You have posted in the parish of Magheracloone so I assume Kate Ward was from that parish. Roots Ireland does not have baptismal records for Magheracloone after 1872 and does not have any church marriage records. Maybe you could contact the parish to see if they can locate a record.