The thing which is not obvious from the skull and which nobody might suspect if all they had was bones, is the way the back of the head goes up to a point to provide leverage for biting muscles.
You have to assume that the same might have been the case with neanderthals.
No, because Neanderthal cranial cases were larger, and the head is largely balanced over the foramen magnum, while the gorilla did not stand upright and balance the head. The gorilla's sagital crest accomodated the jaw muscles, but the occipital crest is where the gorilla's large nuchal (neck) muscles attache to. The head appears very large because of the very large nuchal muscles.