Our strategy, in the face of conflicting diagnoses, some of which we've been skeptical of, is to address the issues that affect my child most at home and at school. It sounds like for your situation, that would be the anxiety. It might take a bit of trial and error to find the right approach to the anxiety. In our house, it's been a combination of CBT, LOTS of exercise (like 6-8 hours a week of running to exhaustion), LOTS of parent contact time, and a very regular schedule. 18 months ago, I thought we were on the cusp of asking about medication. I haven't thought of it or talked to the CBT about it in probably 10 months.
We've also had a very different experience with the anxiety depending on the teacher fit. I have learned a lot about my child from the really fantastic teachers. It sounds like you've got a great teacher right now. If you really trust her, and you think she's got a good pulse of your son, you might consider pretty much laying out the story you wrote above here. Ask her her opinion as an educator as to what she thinks your son's biggest challenges are, and what other kids like your son have needed to succeed. Just be sure to dance this side of asking for a second opinion on a diagnosis, which she's be unqualified to give. However, experienced teachers have seen a lot of kids in their day, and the really smart ones can often give a much more holistic sense of the child than the experts who see you child for much less time and over fewer environments.
I've done this twice now, once for each child. It's worked out well for me, but I've not asked the teachers I don't trust. YMMV
