Especially interesting in the light of Rutzebeck's "Robin Ransor," upthread.

My own guess, however, would be that "Reuben Ranzo" preceded both "Robin Ranger" and "Robin Ransor."

Consider that what's written as "Ranger" would, in nineteenth-century AAVE, most likely have been pronounced more like "ra(y)njah," i.e. non-rhotic, which brings it closer to "Ranzo."

For that matter, "Ransor" may have been non-rhotic too, making it almost identical to "Ranzo."

FWIW