Ellen, There is no such thing as too long in genealogy, only too short.
I am very interested in Cain(e)s so would luv to have the info on Dorothy's step-father Thomas Cain(e)--you mentioned 1910 census and his 1917 Army papers. There are way too many possible Thomas Caines for me to figure out which Caine line he hails from.
Comish is another matter and you probably already have this.
Andreas 1881

04,06,028,COMISH, Edward,B'Syr,Head,Married,37,Shoemaker,Andreas,Andreas

04,06,028,COMISH, Catherine,B'Syr,Wife,Married,37,,Jurby,Andreas

04,06,028,COMISH, Alfred,B'Syr,Son,,13,Scholar,Ramsey,Andreas

04,06,028,COMISH, Catherine,B'Syr,Daughter,,8,Scholar,Andreas,Andreas

04,06,028,COMISH, John James,B'Syr,Son,,5,Scholar,Andreas,Andreas

04,06,028,COMISH, Wilfred,B'Syr,Son,,2,,Andreas,Andreas*
04,06,028,COMISH, Alice Jane,B'Syr,Daughter,,3wks,,Andreas,Andreas

*Wilfred was ch William Frederick

ELIZA JANE COMISH was born 11 Jul 1883 Andreas d/o Edward Comish & Catherine Kelly/Killey

There is a burial for Catherine Comish 6 Jun 1881 Andreas age 45 which would fit the mother Catherine abovre who is missing below.
There is no Andreas MI that I know of for her

1891 Index
Andreas 4684 88 23
COMISH
Edward 47
Catherine Ann 19
Alice J 9
Eliza 7
Wilfred 12

Edward Comish/Comaish might be the one ch 2 May 1842 Andreas s/o Mathias Comish & Ann Harrison who md 30 Oct 1830 Andreas
1851 Andreas
1 15 052 Lhagag
COMISH Mathew Head Married 47 Ag Lab Andreas
COMISH Ann Wife Married 43 Andreas
COMISH Mary 14 Andreas
COMISH Edward 8 Scholar Andreas
COMISH William 6 Scholar Andreas
HARRISON Margt Wifes MotherWidow 84Receives Parish Relief Lezayre

I will follow this query with great interest.
If you wish to contact me, my email is djdorca at sign comcast.net (replace at sign with proper icon)

Donna