Yes, a bunch of what are now called "Child ballads" were certainly sung, amongst a bunch of other stuff. The first question I would ask myself were this my gig is "the music of what class?". What was sung by the Dutch burgher and the English bourgeois would differ somewhat from what was sung by woods workers, farm labourers, teamsters, etc.

Singing to the guitar I think post-dates this era, certainly as regards what we would now call "folk" songs. The whole of the tradition in those days would have been unaccompanied song (whether Child ballad, lullaby, shantyboy song...) and I suspect the bourgeois music would have been piano-, recorder- or lute accompanied.

I think Ontario in this regard would parallel most places in settled North America, with significant differences only in places with an independent tradition, such as Newfoundland, Quebec and the more remote areas in the Applachians.

Good luck in your researches!