Hi, I'm in the military, specifically the Army and began my career as an Infantryman.
1. We have no "definition" of an "assault rifle". A rifle is just a rifle, whether belonging to friendly forces or a threat weapon.
2. A 7.62 mm machine IS a crew served weapon, i.e.: the M240B or the M60 that preceded it. In a dismounted mode there will be a gunner and an assistant gunner who carries a tripod and extra ammunition. A very fortunate gun team (or Squad, since extra ammo will be cross loaded) has an ammo bearer also.
I cannot speak to the accuracy of the rest of your post as the subject matter does not fall within my expertise but I can only hope that it is not equally as poorly researched as your military knowledge.