Look, we may not have no PROOF that Liam iscoming back, but that;s hardly the point. You have no proof that he is and we can't just go around assuming things just because of lack of evidence otherwise; that's not how it works at all.
With everything we have before us- e.g. Liam diretly saying that he ISN'T in it (if he was bound by a contract he would have just avoided the question), the only reasonable assumption to make right now is that he is not back.
We'll see if this changes.