I don't know anything beyond the characters that were in the original OVA's (as well their follow-up "prequells") that featured the actual "JoJo", his father and their bad-ass buddies as they battled the mega-bad-ass Dio.
Everything beyond that-- which can have nothing to do with those characters-- and, I believe, are mostly based on the current mangas, I have no knowledge of other than the fact that I usually can't tell is these characters are supposed to be dudes of chicks or both. Either way, they definitely live up the the moniker of "bizarre".
And so, here is another upcoming release from that line. This guy is called Esidisi. (Go ahead, try to pronounce that. I dare you.) He'll be released some time this month in Japan at about USD 60.00
"Do you think it's time I cut my nails?"
He also includes a second head and, as with most Japanese figures, multiple hands.