Mary Sullivan (nee Sheehan) had three brothers and one sister. The boys all went to live in America, her sister remained behind and married, her name was Margaret Wyatt. It is documented on Mary's marriage certificate that she was a minor when she married Thomas.
Mary Ann Sullivan (nee Soley) had three sisters and two brothers, Elizabeth, Maud, Nance?, Thomas and Jack. Jack was in the Navy and was lost at sea when his ship was sunk in World War I.
Private 12575 John Sullivan was in the 5th Battalion of the Northamptonshire Regiment, he died at the Somme on 13th October 1916, aged 25. His name is on the Thiepval Memorial in France, Pier and Face 11 A and 11 D.
Driver 36030 Robert Sullivan was in 'A' Battery, 77th Brigade of the Royal Field Artillery, he died on 9th June 1917 aged 19. His name is on the Loos Memorial, Pas de Calais in France, Panel 3.
Able Seaman 231415 William Sullivan served on H.M.S. "P.20" and died on 29th October 1917 aged 29. He's commemorated at Kensal Green (St. Mary's) Roman Catholic Church cemetery in London, his name is on the screen wall.