I am sure I have just covered the same material that you have but sometimes new eyes pick out something.
Family tree on Ancestry says he died in Toronto but no date or source is given. Parents given as Frederick and Mary Ann.
Says father Frederick died 1918 so perhaps that is why he was with Barnardos.
1911 census England has Frederick, Mary Ann, William 5, Albert 4, Frances 3 and Herbert 10/12.
Did any of the others to to Canada? Not that I could find.
The March 1927 passenger list I found on Ancestry.ca says
Albert Gibbs, cannot read the age as it is blurred but it definately begins with number 1, born Newhaven England, passage paid by-'assisted', trade in England: grocer, trade in Canada: farming, going to Ont ???? Dept Toronto Ont, farm placement, contact in England: Father, George Payne Gibbs, 6 South? Road, Newhaven Sussex .
You were right about J W Hobday. He is on 1921 census at 52 Peter Street Toronto with wife Rose and children Kathleen, Irene and Clifford. They immigrated in 1921 and he is listed as Manager St Barnados Home.
Passenger List for 1921 says he was escort part of Barnados children to Canada. Had previously arrived in Canada 29 June 1920, leaving 24 Aug 1920 so he was likely an 'escort' then as well. Looks like he made about 5 trips 'escorting' children.
Barnardos address in Toronto is 50/52 Peter Street on his arrival form.
Have you tried this site?
http://canadianbritishhomechildren.weebly.com/There is a William Gibbs, age 20, arrived 1926 on the home children site, going to Guelph. The age is about right but it is a common name.
A lot of the children also went to the Peterborough area.
Can the Barnardoes organization help you out?
I am sure you have gone down every alley.
I haven't found any Wm M Thornton on 1921 census but found a marriage for a William Maxwell Thornton 13 Dec 1907 to Elizabeth McDonald. He was born c 1881, died 1966 buried Dixon Union Cemetery [not far from Brampton].
No Gibbs in the cemetery.
The above Thorntons had a son, aged 11, who died in 1920 of diabetes. Maybe they decided to take in a 'home boy' to fill the gap.
I can find Maxwell on all census except 1921.
Good luck.
There are too many Albert Gibbs on voter's lists to sort out.