Alfred Field is not on the pre-1916 IL death index, but coverage is definitely incomplete:
http://www.ilsos.gov/GenealogyMWeb/deathsrch.htmlMany ships went from Liverpool to Quebec, but there were other routes (including via the US). It would have depended on what was cheapest at the time.
http://ao.minisisinc.com/scripts/mwimain.dll/144/HAWKE?DIRECTSEARCH - can't see them here.
The incoming passenger lists are on the Canadian Archives site but not indexed for 1871/2ish, so that might be difficult to track.
I think daughter Ada might have married as Ada Lucie Field in 1897, to Frederick Stephen Gowar (she is on the 1901 census in Penge, Surrey, 27, born Toronto).
I suspect this might be a relevant entry in 1871!
RG10/3212 folio 157 page 2
Wethley, Warwickshire
John Field, 38, farmer of 260 (acres), employing 6 men, 1 boy, 2 women, b Wethley
Maria, wife, 36, farmer's wife, b. Besford Worcestershire
children, all b. Wethley
John, 7
Maria, 6
May, 5
C Henry, 3
George F, 2
James B, 1
Alfred Field, brother, 18, assistant farmer, b. Wethley
Sarah Mace, governess, 26, b. Dodderham Gloucestershire.
In 1861 Alfred is a pupil at a school in Alcester, and John is with younger siblings Edward (21), Ann (20), and Elizabeth H (16) in Weathley/Wethley/Weethley.
I think I can guess why they might have run off to Canada immediately after the marriage!

Re: Thomas Wyatt and Elizabeth Mace - I believe they married in 1874, she died in 1875, and he remarried in 1878. I can give you 1871 census for him (unmarried) and 1881 (with second wife), if you need them. There appears to have been one child to this marriage, Norah Jane (Elizabeth probably died in childbirth or soon afterwards).