I tried posting this right after Jerry started the thread, but Mudcat crashed for the rest of the day and I saved it. Better late than never:
Actually, those stories are American Indian in origin, most likely Choctaw, to be specific. They made their way into African American folkways, then were appropriated by Chandler.
Trickster tales are common, every culture has them. It is entirely likely that the Choctaw stories were blended with African stories to become what they were at the time Chandler heard them. A problem with trickster figures in the Americas is that christianity had real problems with trickster gods, so they worked to demote and demonize them as fast as they could. The didactic power of tricksters ("don't do this!") was entirely lost on those missionary and settler types.
In American Indian literature circles, Harris is considered to be an opportunist who didn't give credit where it was due.