Umm, first "wrong" grip is actually right. At least in air rifle shooting. I was an NJROTC cadet last year, and was part of the school air rifle team (got transferred to a new school without an NJROTC program). When standing or kneeling we used our hands as platforms. As for second "wrong," it isn't that bad. If a bomb goes off and you are thrown to the ground and insurgents are coming towards you from the left (or the right if you're left handed), one could, in theory, "hug" their SMG, AR, or shotgun and provide rapid suppressive fire.
Probably 'cause they face their bodies more forward ('cause the weak point of body armor is the sides of the body) and they keep their weapon in tight, making holding the rifle by the magwell more comfortable.
No. Aiming up is actually even more slower and awkward (believe me, I tried doing that with my airsoft m4 just now). Also consider that bullets that shoot up (in a roofless environment) will eventually fall and possibly hit someone you don't want to get hit. Better to put a hole in the ground.
One rule that professional gunmen follow is to always keep a certain distance in order to avoid scenarios such as getting disarmed (which is explained in another gun tutorial I did)
Eh, pistols might be an exception of pointing up, because of weapon size.(and weight)
Of course you want to keep a distance from your target, but I was thinking of stuff like clearing rooms swat team style. You end up getting close regardless of what you are doing, and the limitation of openings to be attacked during that is handy.
With shooting up, I don't feel to bad about pointing up if you have any sort of trigger discipline.(thank you spell check)
Because with all of this, I am totally a expert now that I have shot a real pistol at a shooting range.