I hope this isn't considered too much thread drift from the original poster's question, but...

I'm struck by what I call the "faulty exchange" pattern in both of the examples of "The Foolish Boy".

"I sold my cow and I bought me a calf,
By that my bargain I lost just half.
With a whing, etc.

I sold my calf and I bought me a cat,
And in the chimney corner the pretty thing sat".
etc.

I'm wondering, Q, is this the earliest example of this kind of pattern that you've found, and could this be the "prototype" for the use of that pattern in African American verses and songs such as

I went to the river
And couldn't get across.
Jumped on an alligator
And thought it was a horse.

or

I went to the river
And I couldn't get across'
Paid five dollars
For an old blind horse
[p. 185 Dorothy Scarborough On The Trail Of Negro Folk Songs
{Hatboro, Penn; Folklore Associates edition, 1963, originally published by Harvard Univ. Press, 1925}

and

Hush, little baby, don't say a word,
Mama's going to buy you a mockingbird.
And if that mockingbird don't sing,
Mama's going to buy you a diamond ring.
And if that diamond ring turns brass,
Mama's going to buy you a looking glass.
And if that looking glass gets broke,
Mama's going to buy you a billy goat.
And if that billy goat won't pull,
Mama's going to buy you a cart and bull.
And if that cart and bull turn over,
Mama's going to buy you a dog named Rover.
And if that dog named Rover won't bark,
Mama's going to buy you a horse and cart.
And if that horse and cart fall down,
You'll still be the sweetest little baby in town.
[various sources]

-snip-

Is this stretching a search for sources for these songs too far?