THE MAN. I CALL THE SHOTS!"
Look, a lot of your reasoning for not wanting MIL or anyone else around is fine -- my wife only wanted me in the room when she gave birth to our kids, probably for some of the reasons you mention. But that was her choice -- not mine. Now, if your wife asks her mom and sisters to be in the room and they start freaking out or whatever during the birth, it may be appropriate for you to ask them to leave if you think they are some kind of hinderance to your wife's experience in some way. Other than that, you don't get a vote. Deal with it.