I am pretty bad with these kinda issues

But I think it is too late for you to try to make things over again. If something is announced, there is no chance to take it back. Once a decision is made, there is no point to argue, just to get along with whoever is your boss in the future. From what you said, appearently you are not part of the inner circle since you have no clue of who will be added in before it is officially announced. So no chance to get rid of that middle manager between you and M, at least for now. But sometimes, it is better to have a pretection layer there.