This may be a long shot but the name of your great aunt, Cora, rang a bell with my wife's Bradt ancestry. Perhaps Cora's mother was Maybell or Mable, born in 1873, died in 1939, married first to Wm. Milton and later to James Smith.
Mabell's brother, Leonard Bradt, 1886- 1967, married Rose
Billings, died 1963, who was a full blooded Mohawk and was the grandmother of my wife. Maybell's parents were Lucinda Eastman and Leander Bradt who was a civil war veteran from the 58th Pennsylvania Infantry Regiment and both are buried in Manlius Village Cemetery. Contact me if this
information appears to be useful. I have some further information but truthfully am just starting to research this. Whether there were other Mohawk connections I don't know but the Bradts who moved to Ontario would have
certainly had contact with the native Mohawks. Another of Lucinda and Leander's children, Curtis, 1870-1917, married Cora Fox who had a daughter named Marie.