We had the same sorts of problems with DS7 when he was in his dismal-fitting 1st grade class. I don't think he actually punched anyone in school, but he was surly, angry, frustrated, and he cried at the drop of a hat. He was disrespectful to adults and nasty to children. He never got recess because he was always in trouble. He certainly hit his brother at least once a day (and usually more), and he practically never hits him now.
You met him--does all that bad stuff sound like the boy you met?
A bad school fit can cause all sorts of bad behaviors. I understand wanting to deal with other issues if they exist, but I fear that you can't get a very good read on what the issues are (not to mention if they are!) until you have the school fit sorted out, since it can cause virtually every problem you're seeing.
As always, I am no expert. And I realize that to the school, the behavior problems are the bigger issue, and they may not let you solve the fit problems until the behavior is straightened out.
*sigh*
I wish I could be helpful. I'm sorry for your troubles!
