Twitter has been wrong many times before. I've seen two or three reports that Vanessa is returning LOL.
Going off contract doesn't mean he's gone from the show...yet. He could simply drop to recurring. I will say that once he signed onto the Ryan Murphy project, I knew the countdown had begun. RM loves to re-use the same actors over and over in his projects--particularly his anthologies. He will tailor a role for someone. Jessica Lange is terrified of scary movies, but RM pursued her to get her to join American Horror Story and she appeared in 5 of the 9 seasons. She stayed because she enjoyed working with him. NAC has raw talent so I could totally see RM extending the offer to include him in future projects.