FWIW the baby talk thing does seem to be some sort of phase they all go through at this age - all of DD's friends do it and I thought it was some weird craze at her school but I have noticed other kids that age not at her school doing it too. Drives me nuts.
Hopefully you've just got a perfect storm of minor and unrelated issues, but good to keep an eye on it.
Personally I'd ask for the open-minded teacher over the so-far-unhelpful GT coord as teacher. My theory being that the GT coord should be on hand to help you anyway?? Not that it always works out that way
