Continuing down the rabbit hole, here's a supporting piece.

Cameron, Anna Alexander. “Christmas on the Old Plantation.” _The Home-maker_, vol. 3, no. 3 (December 1889): 200-203.

More memories of pre Emancipation Christmas celebration in North Carolina, during the same time and places as the preceding. The author is sister of [Sarah] Rebecca Cameron, of Hillsborough (nee Hillsboro) NC, born 1845.

From UNC:
“The Cameron family of Orange County was one of antebellum North Carolina's wealthiest families. On the eve of the Civil War, Paul Cameron and his siblings owned over one thousand slaves and nearly thirty thousand acres of plantation land in Orange, Wake, Person, and Granville Counties, as well as plantations in Alabama and Mississippi.

Paul and Anne Cameron [parents of the sisters] lived at Fairntosh from 1837 until the late 1850s, when they moved back to Hillsborough.”

From the piece:

//
I allude to the custom of “Coonah dancing.” It is said to be a direct importation from Africa, and has been handed down from generation to generation.

… They bob all around, like so many tottering, awkward goblins, chanting in a low, monotonous tone, when, all at once, from amongst them, spring ten or twelve, or more…the banjos begin to play spiritedly, the bones and triangles to rattle in perfect time, and mellow voices break forth into the “Coonah” song. …

The song is very spirited and sung with an abandon of enjoyment, and yet though it is the very voice of gladness and mirth, deep in the heart of the melody is that pathetic cadence which is the soul of negro minstrelsy. …

From house to house they go, everywhere receiving more or less liberal contributions of money and Christmas cheer. …

This, amongst many other familiar customs, is now a thing of the past,…

“Dance, dance my Coonah John,
        Ho! Lady Sorna,
Coonah’s dance for one cent,
        Ho-sang-du-sanga,
Jump, jump, oh! Coonah John!
        Ho! Lady Sorna!
Pop your whip, oh! Coonah John!
        Ho-sang-du-sanga!
Turn your partner, Coonah John!
       Ho! Lady Sorna!
Hands up fo’ oh! Coonah John!
        Ho-sang-du-sanga!
Swing your corner, Coonah John!
    Ho! Lady Sorna!
Honor your partner, Coonah John!
        Ho-sang-du-sanga!”
//

"du-sanga" doesn't feel like a satisfying connection to "ranzo," unless we account that Sarah Rebecca remembered it as "du-rango," and from there to "ju-ranzo"!