I can't think of any modern day separatist groups that are collaborating like the examples you've given, but, at this point, it wouldn't take much to get a lot of black Americans (with American ancestral lineage that goes back many generations) to permanently relocate out of America. There's been an uptick these past few years of black Americans moving to Africa, particularly Kenya and Ghana. If the Trump administration were to offer black citizens $500k (heck, maybe even $300k), I believe many would take it.