Hi River,
You probably already have this, but here is the family in the 1901 census.
Class: RG13, Piece 5305, Folio 6, Page 3
Isle of Man, Civil Parish of Conchan, Ecclesiastical Parish of Douglas St George, Town of Douglas
14 Bridge Road
John Thos Cain, Head, M, 37, Coal Carter, Worker, born Isle of Man, German
Julia Jane Cain, Wife, M, 36, born Isle of Man, Patrick
John Jos Cain, Son, 7, born Isle of Man, Douglas
Catherine Elizth Cain, Daur, 1, born Isle of Man, Douglas
Harriett Comaish, niece to wife, S, 19, General Servant Domestic, Worker, born Isle of Man, Lerayro
Edith Comaish, Daur Boarder, 1, born Isle of Man, Braddan
I apologise if the town names are incorrect, I know nothing about the Isle of Man (other than they have great Harry Potter stamps).
I guess that Edith may be the daughter of Harriett. I only guess this as she is listed below Harriett with Daur crossed out.
Debbie