There is a plot in Mount Pleasant Cemetery in Toronto that was owned by William John Johnson, and buried in that plot are:
John Urquhart, 58 years old, born Scotland, died Nov.4,1891 in Toronto, buried Nov.5th.
Roy Johnson, 3 years old, born Toronto, died April 29,1889 in Toronto General Hospital, buried April 30th.
Isabel Johnson, 21 days old, born Toronto, died Sept.2,1893 in Toronto, buried Sept.2nd.
Alexander Urquhart Jr., 3 days old, born Toronto, died March 29,1899 in Toronto, buried March 30th.
I could not locate a stone.
There is a single grave in Prospect Cemetery in Toronto that was owned by Roderick Urquhart, and buried there is:
Janet Urquhart, 78 years old, born Scotland, died May 28,1911 in Toronto, buried May 30th. I could not locate a stone.
I did not find a death notice or an obit for John Urquhart, but I found both for Janet.
Toronto Telegram, Monday May 29, 1911:
URQUHART - At her late Residence, 174 St. Clarens Avenue, on Sunday morning, May 28, 1911, Janet Urquhart, relict of the late John Urquhart, in her 78th year. Funeral on Tuesday May 30th at 2:30 o'clock. Interment at Prospect Cemetery. Collingwood and Stayner papers please copy.
Toronto Telegram, Tuesday May 30, 1911:
Mrs. Janet Urquhart - After a brief illness, Mrs. Janet Urquhart, relict of the late John Urquhart, died on Sunday morning last. The deceased lady was in her 78th year. She was born on the island of Islay, Scotland, and came to Canada with her parents in 1833, being the past forty-five years a resident of Toronto. Deceased leaves sons and daughters to mourn the loss of a devoted mother, as follows: Roderick, Archibald and Mrs. Woods, at home; Mrs. Johnson of College Street; and Donald of Wells Street. She was for many years a member of Ronar Presbyterian Church.
I believe I found John and Janet in the 1861 census in Nottawasaga Twp, District 1, Simcoe County, Ontario:
John Urquart, clerk, Scotland, Church of Scotland, 26, married, 1 family in 1 storey frame house.
Isabella Urquhart (Janet), Scotland, 24, married.
R (Roderick), Canada, 3.
Isabella, Canada, 2.
There was this daughter, Isabella Sutherland Urquhart, that I missed finding earlier. She is obviously named after her father's mother. Here is her marriage record:
#13049-79 William John Johnson, 23, born Toronto, living in Toronto, bachelor, malter, son of Arthur and Margaret Johnson, married Isabella S. Johnson, 20, born in Canada, living in Toronto, spinster, daughter of John and Jessie Urquhart. Witnesses: Thomas Cooke and Ellen Parker, both of Toronto. Married Dec. 8, 1879 in Toronto. Groom: Church of England, bride: Presbyterian.
Children born to William and Isabella were:
William Clarence Nov.3, 1880
Female April 4, 1882
Donald Arthur March 3, 1884
Byron Roy May 16, 1886 - April 29, 1889
Edgar Dec. 26, 1888
Isabella Aug. 12, 1893 - Sept. 2, 1893