I think its a great idea having the mask plug into the face. Every time its a perfect fit and its tightly on. I am not confident that even if you took the mandibles out of Classic's masks they would fit onto the P1 as the head's are quite different in shape as well as size. It could probably be modified to work to an extent but it wouldn't be a straight forward thing to do.
About the waist armour, Classic is slightly bigger than p1 in the thigh and hip area so it wouldnt be a perfect match but it could be done. But it might be a struggle to clip in at the back of the belt. I think it would just be better to neatly remove the pouch
About the waist armour, Classic is slightly bigger than p1 in the thigh and hip area so it wouldnt be a perfect match but it could be done. But it might be a struggle to clip in at the back of the belt. I think it would just be better to neatly remove the pouch