Anything can happen, but I'd be surprised if they announce a new manager before announcing GP has gone. Also, I think it's fairly unlikely they'd announce the two things at the same time. I would expect one announcement, and if they have someone lined up, at least a day before they announce the replacement.
Not to mention playing right into GPs hands in terms of constructive dismissal. If you are having a disciplinary hearing you have to enter it with an open mind not having already appointment the next manager!