Adolescents don't have the developed perception of consequence as adults, and yet OP is already pinning them with mental disorders that can't be resolved. Pure speculation that is outright wrong.

In the case that you mention with learned anti-social behaviours, counselling can most definitely help with unmapping/correcting those behaviours.

Um, I never said that. I talked about tendencies, just like you did. It's not very meaningful to say what bullies "are", but bullying does generally involve at least some degree of instrumental aggression and callous/unempathetic attitudes. Such attitudes might arise out of simple imitation like you said, but only if someone else is actively demonstrating them - and this will generally be someone in the peer group who holds significant social influence on others.

Yup, that's the real issue. The sociopaths and narcissists may only be 2% to 4% of the population but those are the actual bullies, so to speak - those who are most clever at manipulating others into adopting similar behaviors and attitudes. Thus some youths who seem to be bullies may actually be victims of manipulation by somebody they look up to, but they will stop their behavior once the attitude around them changes for the better.