And even though the plotline is moving away from the Flashpoint arc, Eddie could always be another loose thread from Barry’s timeline-switcheroo, still alive and walking around Earth-1.
Eddie could also show up as a hallucination of Barry’s (or another character), something that Arrow’s Oliver Queen knows a lot about.
However it goes, it’ll probably be exciting, especially if we get to see Rick Cosnett get angry.
Or, with all that Barry has gotten help from Earth-3’s Jay Garrick, perhaps that other-dimensional location will be where Eddie Thawne reappears, similar to how Mark Hamill’s Trickster showed up in the mid-year finale.