Ellen Mary Coyne : Short Biography

My g-grandmother, Ellen Mary Coyne, arrived in Australia in 1864.  Her shipping record states she was from Westport, Co Mayo, and her parents were John Coyne and Honora McAnally (McNally?) and that she was 19 years old, which gives her a birth year of c 1845.  The shipping record also states that both parents were deceased.  Ellen married Ringan/Robert Johnston (from Belfast) in 1870 in Newcastle, NSW.  After his death in 1872, she married my g-grandfather, William Byron (from Tipperary).  Ellen and William had 7 children, one of whom was my grandmother.  We have been unable to find out anything about Ellen prior to her leaving Ireland and have no idea about any siblings/family.