More wonderful messages while I was off to the opthamologist. First of all, Kiltaglassan and rosie17, that would be the correct Lena Watterson who married David Crossett in 1920 with father Ignatius.
At birth, Lena was registered as Fanny Watterson May 23, 1897. On the 1901 census, she is Helena Watters and on the 1911, she is Lena Watterson.
Mary was Mary at birth Mar 24, 1902 but Sarah on the 1911 census. Now we have tracked her till her death in Brooklyn, thanks to all your wonderful help.
Benjamin was born Aug 11, 1895 in Ballymulderg More, Co. Derry, but the family moved down to Mullan, Co. Tyrone. He was still alive in 1936 when his mother died.
Margaret on the 1911 - I did not find her birth abt 1904. Her only brother that I know of was Benjamin.
Sandra, her details do not fit the Margaret Helena Watterson born 1907 Lisnamorrow with brother R. J. Robert in Belfast and brother Joseph in USA. I do have a Margaret born 1890 in Ballymulderg with brother Robert John born 1885 but no brother Joseph unless I am missing him. I believe this Margaret has been mentioned before and I couldn't place her then and I still can't. Something else I must pursue as I am now intrigued. She should be on the 1930 census at 556 West 140 th Street New York since she was in the USA Nov 1929-1935.
As for Samuel, who died 1954, it was his wife Margaret nee Bell who died in 1937.
There is another Mary Watterson who lived at 2095 Nostrand Ave., Brooklyn in 1927 as did her cousin Elizabeth Watterson (Elizabeth was sister-in-law to Samuel George Buick). I haven't figured out Mary as yet.
Thanks again all of you.
Peggy