Obviously he has no consequences that he cares about.
1,2,3 only works if it is followed by immediate consequences he cares about.
Here are a few things to think about:
1.) Do you follow through. If you say it, do you mean it, do you follow through immediately
2.) Have you thought about stepping up the consequences to a point in which he cares. (my daughter will fall asleep in time-out but hates standing in the corner) And if the circumstances warrent it (like direct defiance...telling me no, or breaking a rule repeatedly for days regardless of consequences, meltdowns, or hurting someone intentionally) she will get a spanking.
Guidelines for a spanking:
1.) Always in private so you aren't humiliating them in front of peers.
2.) Talk to them about their behavior and make sure they understand why they are getting spanking.
3.) After spanking them, make sure you give them a little time to cry.
4.) Go back re-explain why they got a spanking. Explain that you love them and they have to behave and follow instructions. They must obey you or they will be punished. (I know most don't like the word obey, but that's what they are doing when they follow instructions so we just need to get over it).
5.) Hugs and kisses and a final firm but loving reminder that there are always consequences for our actions and we must think before we act.
He's not responding because you haven't found what he cares about.
You have to do some soul searching and figure out what you want from him, how to get that, and decide that you will always be consistent, fair, and unwaivering.
PS My girls had to endure a bully for almost two years before he grew up enought outgrow his aggressive nature. It was very frustrating for us as parents since we didn't like to see our girls get abused and tortured when they just wanted to play. It took all the strength we had to try to deal with the problems in a calm way. I finally had to teach my girls to throw a punch so that the bully would realize that there were consequences for his actions...my hubby had to jump in on a few occasions to put the fear of God in this little guy. No child should have to endure a bully and then see the bully get away with it.
Our criminal justice system is full of that. More rights and concern for the criminals than their victems. He needs to know that it's not acceptable to bully other kids. It's natural for some kids to be aggressive....he's a boy and I would rather see an aggressive boy than a whiney, cry baby. But you have to make sure that other children are safe and if you have to step in between him and the other kids every second then that may be what you need to do. He has to suffer in some way that makes him want to curb his behavior.
I hated having to follow my girls around trying to protect them from being whacked over the head with toys or their head being stepped on when they were just crawling. It wasn't fair or right that they had to endure scratching, hitting, and pushing at every turn.
Honestly, it really didn't stop until the little guy in question got a little brother that he started abusing and then he suffered some consequences he understood (spanking) and he stopped. He rarely if ever hits anyone anymore. He's actually a pretty sweet guy now.
Spanking does not make violent children. It teaches them that hitting hurts and it's not something we want to do to others or that we want done to us. And if they know that is the consequence for their behavior they will stop.