Haven't read all the thread but had a very similar experience with a livelier, louder and more inquisitve than average DS whilst being surrounded by calmer more complient children. It was really hard not to feel negatively judged and sometimes felt that I was yelling at him all day to make him conform to what others expected.
We sat down and worked out a scale of behaviour; these things are important and always enforced (Safety, respect for others), these things need to be checked in their context (being boistrous, shouting, etc) and these things really don't matter.......? I have tried to stick with it (not always easy) and the important thing really is that they are OUR rules and we have thought about them. I really care about what other people think and know I shouldn't so that's another struggle but I'm working on it.
We also have a problem with 'sneaky' children who know how to be provocative without being caught,a couple do things like edging other children behind their mums before giving a bit pinch. My DS doesn't have that nous and always get caught for retaliating (he's as capable as any at initiating it too though). Be sure that you're seeing the whole situation. Also 'blind' mums who only tell off other children.
Positively though he's just started school and is like a different child, I really tried to keep him engaged and interested as much as possible but he was bored to tears at pre-school and is stretched and challenged at school. The child that everyone regarded as a 'problem' when younger has been described by his teacher as a breath of fresh air and a joy to teach. So there you are, a happy ending.