I always took it they were making a play on the fact that the show's version of Oprah Winfrey of course achieved her heights of importance in the culture because of witchcraft, or a deal she'd made with a dark power...but they haven't done much with her fame otherwise. Done anything with it, actually. So, good question.
Re: timing of main flashbacks relative to apocalypse (the word apocalypse is so tedious to type, maybe I'll just call it Apoca) - that would mean that the version of Langdon that Cordelia is familiar with, from having just recently resurrected Misty and Madison and Queenie, is only months from being the Langdon who strolled into the bunker with his long luxurious hair and having made pre-arrangements for the outposts and the Adam and Eve selection? It seems like Apoca is farther off than that, and his development from the schoolboy who just aced the Seven Wonders test into who he was post-Apoca will take longer. Coco to me doesn't seem like the version of Coco we met back in the first episode, who's in a long-term seeming relationship with Billy Eichner. (This version of Coco has been living in NOLA learning to count calories, so she hasn't taken up yet with Billy on the Street?) I think they've overestimated our interest in how an X-Men team of witches got assembled so long before the apocalypse, since we already know that wasn't enough to prevent the event from happening anyway.