Qi gong is strictly speaking the manipulation of qi, which is the same as the vital force of the hermeticists.
Iron body is a training regimen that may but does not have to utilize qi, and the purpose is to make one's body more durable.
Golden Bell is the logical extension of iron Body that supposedly lets one use qi to absorb the force of an attack.
Breathing techniques are by themselves methods of calming the mind and body, but in conjuction with qi exercises or yoga produce a superior result from practice.
All of your posts seem to focus on the wrong aspects of the wrong things and come across as really dismissive.