For some reason this old song came to me this evening, so I googled it and found all this information. My grandfather taught my mother who taught me. I presume his father, who was quite an accomplished amateur singer and piano man, taught him. My mom was born in 1928, so that would have been comtemporary music when my grandfather was a kid.

I never got as far as the baptism lyrics, but I never heard it as anything other than "coon preacher"

That would have been around Windsor Canada. Music travels.