As you probably know by now, my interest in Wm and Eliz CAIN (m 1865) is strictly Clague based. And Eliz’s line has lots of those since both parents started off in life as Clagues.

After finding Wm CAIN’s info in Manx memorial notices, the most interesting thing I have on the couple to me is their 1861 census entry.
1861
Seen on Ancestry July 2, 2010
Braddan E.D. #2 page 15 Household 68
RG9/4412
West Division
Castletown Road
George Goldsmith head mar 56 miller Kirk Christ Lezayre
Jane Goldsmith wife mar 52 wife Kirk Lonan
Ann Goldsmith dau un 20 dressmaker kirk Braddan
Frances Goldsmith dau un 15 scholar Kirk Braddan
Elizabeth Clague servant un 20 house servant Kirk Braddan
James Caley servant un 17 mller Kirk Lonan
Wm Cain servant un 20 laborer Kirk Patrick
IGI Individual Record FamilySearch™ International Genealogical Index v5.0
British Isles

Household 68 in Braddan E.D. 2 is not far from the census listing for Eliz’s parents at Household #17 which is not all that far from Eliz’s uncle and my forebearer at Household #27. I have often seen women put in service in their late teens and early twenties but seeing Wm Cain already out of the nest of course I had to check to see how that came to be and discovered that after his father died before the ’51 census; Wm’s mother married jail bait ( nineteen year old? Geo Jas Clucas) but after about a ten year marriage also died whereupon Geo. took a second wife and I presume lived happily ever after.

I also have the Wm and Eliz CAIIN household in the 1871 census.
RG9/4412
1871
Seen on Ancestry July 2, 2010
RG10 Piece 5776 Folio:169 Page 22 GSU Roll 895845
Household 804
12 Fort Street Court Onchan St. Barnabas Douglas
William Cain Head Mar 35 Police Constable Patrck, IoM
Elizabeth Cain wife mar 30 wife of do Santon
Robert C. Cain son un 3 Douglas
William Cain son un 2 Douglas
Elizabeth C. Cain dau 1 Mo Douglas

Using the next three censuses plus the IGI plus your handy dandy tombstone inscription: I have a list of nine little CAINs to the family and I must say. The naming patterns are totally fascinating:
Descendants of William CAIN

1 [1] William CAIN 1839 - 1917

. +Elizabeth Clague 1840 – Maybe 1932
.. 2 Robert Charles CAIN 1867 -
.. 2 William CAIN 1869 - 1898
.. 2 Catherine Elizabeth CAIN 1871 - 1875
.. 2 Thomas CAIN 1871 - 1872
.. 2 Isabella Ellen CAIN 1874 - 1960
.. 2 Thomas William CAIN 1878 - 1881
.. 2 Elizabeth CAIN 1880 - 1884
.. 2 John Edmund CAIN 1882 -
.. 2 Lewis Newell CAIN 1886 - 1965

Your latest MI tells me something about Lewis Newell. More is to be done there.
What became of John Edmund and Robert Charles; I know not. One of the two according to the Memorial Notice has to have been dead by 1917.