Funny you should mention Rock and Roll as I was just thinking about the word Zydeco which is a corruption of Les haricots, and how such words come into being.
I find it unlikely to have been the port of Hilo which makes this name occur so frequently in song, as the gulf ports were visited far more often and yet relatively rarely appear in song.
High-brown and Low-brown were common references to depth of colour among slaves, a fact not yet mentioned.
I am not drawing any conclusions here, merely muddying the waters that you seem to take such delight in wading into. :-)