Answer
Q66: the momentum given to the clothes is matched by an equal and opposite momentum of the thrower, resulting in zero net momentum for the system of person + all clothes.
Q67: According to Newton’s third law, whatever force you exert on the ball is balanced by an equal and opposite force that the ball exerts on you. The forces on the ball don't end up accelerating it, so neither will the forces on you cause an acceleration of your body.