Great, I almost forgot to say thanks! And for the
explanations also. I'm still not sure
if McMichen did use those all those words above,
but probably it is as close as we can get in this case.
At least now some of the rhymes make sense.

I have not encountered so hard-to guess/hear words
at that many times, some variations appear on
Uncle Dave and the Fruit Jar Drinkers's tunes Tom & Jerry
and Sleepy Lou.
And Skillet Lickers' Molly put the Kettle on.

As you say, these rhymes sound more like some sort
of imitation of what the dance callers say. But the words
make the tune lot more fun to play. Especially tunes like
Flatwoods need some kind of singing or shouts.