I'm not going to post actual messages, but from what I have heard from Marbury himself(I'm not talking about just twitter replies), he has no idea where he is going.
So anything you are hearing from people is pure speculation.
Is there a possibility that he will be back? Of course. But it doesn't appear that there has been any talk between the two sides on making it happen.
It also seems that Marbury might have "declined" the original offer because the Celtics wanted a quick signing if he was on board, but Marbury was not ready to make a decision that quickly, so he declined.