Everyone is assuming the realm is united against him. That isn't necessarily the case.
Of course if the realm is united its easy to cause enough trouble to make him leave. I'm talking about the possibility of being removed from normal in game plotting or efforts.
No, it isn't. If you have a lot of active players willing to dedicate a significant chunk of time to aggravating him, you can make him very aggravated. But if he's ornery enough, he can stay
anyway.
There is no way to
make a Royal leave unless he's dumb enough to, say, rebel against you and lose.