You are doing a great job. I just want to reiterate that.
Her behaviors sound like my son's behaviors when he's not meticulously managed - for us that means a LOT of sleep (he has to be drugged to sleep as much as he needs and it requires a specific routine), no dyes not in food, soap, or art supplies (he cannot touch crayons for example), and other dietary restrictions, and he is also on stimulant medication.
So I am just offering that to say that these behaviors don't always stem from abuse/neglect. I have no idea why other than food/dye sensitivities and ADHD, but dh and I both had that moment when we were sitting in foster parent training listening to the description of the abused/neglected child and then panicking that we had done something horrible to our own child
Have you talked to the parents? Are they helpful at all? I agree that it sounds like the teacher is a big problem. Can that be reported to someone?