Well, just watching episode 11x12 of The Walking Dead and we realise who the real Stephanie that Eugene was talking to was.
Character profile - https://www.tvmaze.com/characters/673272/the-walking-dead-stephanie
Now, we have Margon Bingham playing Stephanie in season 10 if she was voice of Stephanie, but later when we meet her, she isn't the real Stephanie, but the fake one. However, not sure if in season 10 her voice is supposed to represent the real Stephanie.
Either way, there should be split there. In fact, at the end of episode 11x11, Lance Hornsby character tells Eugene the real name of the fake Stepahnie (Sheila or something, I believe, I should check it again)... so, perhaps that should be used in place of fake Stephanie.
The way current Stephanie's character page looks like is like two actors played the same character, but they didn't. One was real, and the other was just pretending to be the other one.