polarbear,
First off, what a rotten second grade teacher! She deserves an apple with a worm. Perhaps we should start another thread entitled the Wormy Apple Award and you can nominate her.
Secondly, my son sounds a lot like yours. Right down to avoiding the academic work in the Montessori preschool. He does not enjoy school work at all.
Another thing I wanted to clarify is that it is not just "b and d" and "p and q", it is all four together. He doesn't just reverse, he flips too. Hence the "u and n". His favorite letter is "o". He says he likes it because it is easy to write and it is always the same.
He had a vision screening with a pediatric optometrist recently and there were not any issues.