And since the Familysearch entry neither links to an image nor transcribes all the information, here is a link to the page image.
The record indicates Robert was born in Ontario, his father in Ireland, and his mother in Ontario.
The best fit I initially found for an earlier record is in the 1871 Census where a Robert Wellwood, age 9 is enumerated in the household of Joseph Wellwood (born in Ireland) and wife Johanna (born in Ontario). The family resides at Goulbourn, Carleton Co.
This record gives me confidence that, despite the difference in recorded age, the Robert named in the household of Joseph Willwood at Marquette in the 1881 Census is also the same person. I would also highlight the last family on the same page is a George Allbright and family.
The connection to Carleton also leads me to this page of transcribed Birth/Baptism records where we find Robert Welwood (sic) son of Joseph and Joanna born 3 Oct 1861 - which appears to validate the DOB your Aunt Hattie gives. (A number of siblings are also listed). The index of the Manitoba vital stats website also confirms the given marriage date for Robert Wellwood and Mary Hattie Clarice Albright as 31 Oct 1882 at Westbourne (Marriage Registration 1883-001391).
While searching for Robert's death date I did find the indexed death date for his father Joseph who died at Westbourne on 25 Apr 1886, aged 67 years. (Death Registration 1886-001501)
Further, I would also identify an 1874 marriage of Margaret Wellwood to John J. Lackey at Goulbourn (Carleton Co, marriage reg. #2034) with the eldest daughter named in the 1871 census record which names her mother as Johanna BURROUGHS
I also see the possible source of confusion, in addition to 'your' Robert Wellwood (b. 1861), there is also a Robert George Wellwood (b. abt 1868) found throughout the provincial records.