I know this is an old thread but I stumbled across it and may be able to provide a lead. As you know James C went to Australia. One of his sons, George Edward (my grandfather) came on ship Miltiades in 1909 with Cissie bumstead. The passenger lists state George (aged 2) as Cissie's brother. Could this be Sarah?
According to my father, George E referred to her as Aunt Cissie, she never married and lived to be over 100.
Also James C had children with Esther Harriet but i am not sure if they were married as she sometimes was referred to as Esther Harriet Norris.
Let me know if that helps
GB
see:
Mariners and ships in Australian Waters: MILTIADES
http://mariners.records.nsw.gov.au/1909/11/094mil.htm