Thanks, Q, for all the info. I have recently ordered and received a copy of Fowke's Penguin Book of Canadian Folk Songs and I vouch for your representation, except that the version from Mrs. Fraser does carry a date (and place), 1961 (Lancaster).
I think we can be certain that In the Bright Mohawk Valley is not a phantom. Steve Roud tells us,
"Delaney's Song Book No.13 [Sep 1896] p.18 has a text of IN THE BRIGHT MOHAWK VALLEY, headed 'Words and music by James J, Kerrigan, copyright 1896 by Howley, Haviland & Co.'" This fits the information provided by Fowke in Western Folklore 23 (1964). Indeed, it is possible that Delaney's is Fowke's source. I will try to verify with Steve that the words in Delaney's are the same as those printed by Fowke.