There is no suitable place for an Octopus to wear either pants or a skirt. Octopuses are almost entirely made of face. There is no torso, no waist, no lower body. We call the appendages around the mouth “arms” (not “legs”) but they are more analogous to prehensile whiskers. I think they would be more likely to wear a cap or headband. A balaclava would be interesting.