>he’s (Billy Kersands) credited with the song ‘Old Aunt Jemima’

There's evidence that Billy Kersands did not write the song, but was rather a later performer of it. The originator was more likely a white minstrel named Joe Lang. (I think the idea that it originated it comes from Toll's book _Blacking Up_ [1974].)

>Dramatization of Juba dancing in a competition:

This is unclear. The link appears to conflate "patting juba" with the dancing by the individual, Master Juba. The word "Juba" is there in both cases, but as far as I was aware they are not the same. Patting juba is the performance of body percussion (rarely referred to as a "dance," in my experience) whereas Master Juba was a dancer... who danced... but didn't pat juba. (Clear as mud?)