These might be a possibles - perhaps try and contact the Thunder Bay Library to see if you can get copies of any obit to check if Margaret/.Peggy is mentioned ?
INDEX of death notices, obituaries, In Memoriams and estate notices
published in the Fort William Daily Times-Journal 1900 - 1972
Page 212 - Thomas Dickinson - aged 66 years - Fort William - died 27 January 1957 - obit placed 28 January 1957
https://www.tbpl.ca/wp-content/uploads/sites/146/2023/10/fwdtj-death-index-1900-1972.pdfYou could also try Peggy's brother Donald C McLeod to see if she is mentioned. - 1896 - 1963 - passed aged 64 years - Fort William - 19 March 1963 - obit date 20 March 1963 - page 3.
https://www.tbpl.ca/wp-content/uploads/sites/146/2023/10/fwdtj-death-index-1900-1972.pdfanother sister Christina/Chrissie (nee McLeod) Black - 1894 - 1985 - passed away aged 89 years - 13 July 1985 - obit date 15 July 1985 - page 27
https://www.tbpl.ca/wp-content/uploads/sites/146/2023/10/CJ-Obituary-Index-1972-1989.pdfanother sister Jessie (nee McLeod) Bates - 1906 - 1989 - passed away aged 83 years - 8 Dec 1989 - obit fate 11 Dec 1989 - page 22
https://www.tbpl.ca/wp-content/uploads/sites/146/2023/10/CJ-Obituary-Index-1972-1989.pdfIn Memoriam for brother Matthew (passed away in Minnesota):-
McLeod, Mathew n/a 12 Sep 1936 In Memoriam 11 Sep 1937 p.15
McLeod, Matthew n/a 12 Sep 1936 In Memoriam 12 Sep 1938 p.15
McLeod, Matthew n/a 12 Sep 1936 In Memoriam 12 Sep 1939 p.11
Sandra