Dude, if they have a smidgeon of semitic ancestry that’s all well and good, but the whole “intermarrying with the native black folk” thing would require that the output of their unions, 3,00 years later, would most likely appear to be 100% african folks, albeit with little skullcaps on their heads and Stars of David on their tombstones.
I guess I was assuming they had females as well as males among them, and that they followed the laws against intermarriage with non-Jews.
They were following other laws, so of course I thought they were following all of them.
The Jewish people has always been a rather genetically varied group that, while it did not seek converts, accepted them.
FWIW, this group, practicing another religion (Christianity, Islam) would not be eligible for immigration to Israel under the right of return.