None of the things you list in your post are (necessarily) illegal. It is legal to follow someone. It is legal to defend oneself. In Florida, specifically, it is legal to use lethal force to defend yourself in a in a fight you started, if you are in reasonable fear of death or serious injury, and have no other means of escape.
You may disagree with these things being legal. That’s fine, but Zimmerman must be judged based on the laws that applied when he acted.
You may think it’s likely he broke the law, but unless it can be proved beyond reasonable doubt - a concept Bricker has just once again explained, and has done so extremely well - he may not be found guilty, and he may not be punished. That you would call for this to happen when the evidence does not show him guilty beyond reasonable doubt shows the contempt you have for the justice system.
I want a justice system that allows anyone to walk free, unless it can be proven beyond reasonable doubt that they committed the crime they are accused of. No ifs, no buts, no probabilities or likelihoods. Proof or STFU, basically.
This case boils down to a simple point, really. Was Zimmerman entitled to shoot Martin? The state, to convict, must prove he wasn’t, which will entail proving, beyond reasonable doubt, that Zimmerman was not in reasonable fear of death or serious injury, or proving both that he was the aggressor and that he had another means of escaping the fight that shooting Martin, after the point he became in reasonable fear of death or serious injury.
All the other discussion - did Zimmerman chase Martin or merely follow, did Martin double back, was Martin justified in striking Zimmerman - is ultimately irrelevant to this. The only way it could be relevant is if it is decided Zimmerman was not justified in defending himself with lethal force, to determine whether it was murder or manslaughter. I do not believe it will come to that.
You, on the other hand, seem to neither know nor care how the justice system actually works, and want a system that simply says “I don’t like what he did -> He must be guilty of something -> PUNISH HIM!” That is unacceptable, and it is from people like you that the justice system has been developed to defend us.