All along, I've agreed that Zimmerman was pretty foolish to be pursuing Trayvon, especially since he'd already notified police. He should have gone back to his car and stayed there. Even if Trayvon were actively committing a crime (which he was not), Zimmerman's no cop - he should have stayed out of it. The safest thing to do in that situation would have been to be a good witness.
I'm not as certain as you are that the Stand Your Ground law would be on Trayvon's side, though it's entirely possible. If Florida considers following someone as aggression, then you're right (and a lot of people in Orlando are criminals).

What is the point of rules that are not enforced?