Quite certain now that this is not my great-uncle's family but am posting the research concerning them in the chance that it might help someone else.
The marriage 1901 is from the Manitoba Vital Statistics Database: WPG 17/05/1901 George Jennings m. Helen Campbell Marriage Place: Winnipeg, Manitoba, Canada URL: http://vitalstats.gov.mb.ca/Qu.http://vitalstats.gov.mb.ca/Qu.. NOTE: Interesting that in the transcription on line the month is written in French as "mai". This might suggest a French speaking official, possibly a Catholic priest, though there is no other reason to suggest this.
The birth of daughter Evelyn is from the Manitoba Vital Statistics database: REGISTRATION NUMBER: 1900-17710533 The child has the last name of Jennings, no father is mentioned, and it is unknown if the parents are married to each other. Mother is named as Helen Campbell. Date of Birth: 15/02/1900 WINNIPEG NOTE: The date of registration is: 19/06/1952
GEORGE JENNINGS is born on 17 / 04 / 1902 at Winnipeg, Manitoba to Helena Campbell; No father's name on-line, but the parents are married to each other. No registration date is shown on line. (Not on 1901 census, because he was not born yet.)
Saskatchewan Vital Statistics Registration Number: 1845 EDITH JENNINGS is born on 1904 / 11 / 25 at Skull Creek, Saskatchewan to HELENA CAMPBELL JENNINGS and GEORGE JENNINGS
Saskatchewan Vital Statistics Registration Number: 2975 LAUNA JENNINGS is born on 1906 / 10 / 29 at Skull Creek, Saskatchewan to LEMA CAMPBELLand GEORGE JENNINGS ( I took the liberty of transcribing this as Laura, but it might also be Lorna)
Saskatchewan Vital Statistics Registration Number: 3623 SARAH IRENE JENNINGS is born on 1907/12/2 at Skull Creek, Saskatchewan to HELENA CAMPBELLSand GEORGE JENNINGS
William is a four year old on the 1916 census.
Archie is a one year old on the 1916 census.
The following death registration for a George Jennings in Saskatchewan is not for either the father or son in this family, since both are listed on the 1916 census. Saskatchewan Vital Statistics Registration Number: 1190 Last Name: JENNINGSFirst Name: GEORGE Sex: M Death Date (yyyy/mm/dd): 1906 / 11 / 28 Place of Death: (I may have to spend the money to get this complete information.)