The first rule here is that if the child doesn't advocate for herself, you have to be her voice. But it sounds like you're already doing that. Kudos.
The second rule is that no amount of skillful advocation is going to win you a single concession that the school adamantly will not do. We faced a similar stonewall for our DD on a grade skip, which we finally solved by going around them - we withdrew our DD from public school as a 2nd grader, registered her with our state's DOE as a 3rd grade homeschooler, then reintroduced her to public school the following year as an incoming 4th grader.
My DD is now 12 and in 8th grade. I recently met with her English teacher, and she expressed her sympathies and horrors at DD's previous experiences with school. It seems DD had made it the topic of a writing assignment, and in particular her K experience was still bothering her all these years later. All this to say that if you can do something about this, better sooner than later.
