Follow up on tracing my ancestry

So I’ve eliminated my entire grandpa’s side, and there are just four remaining possibilities. One of the four would mean I don’t need a geirus. And I have no clue how to get Greek records, because that’s where all the information on the last four possibilities is. The Geek Jewish Museum had nothing, I need maiden names now because all the possibilities are women but I can’t find them. Anyone have any other ideas? I emailed the Chabad of Athens to see if the rabbi there can help me, but other than that I’m clueless.