Thanks to all for the thoughtful feedback. It is reassuring to know that others have worked past these levels of anxiety and seen success by pairing with strengths and having flexibility to find a way the child can do it.
Unfortunately, we are not in a city with a 2e specialist. We are getting testing from an academic children's hospital though. But my stomach lurched when I listed "gifted" as one of the things that I wanted to have assessed and the intake secretary said "we don't work on that end of the spectrum." I hope the actual neuropsychologist is better informed/experienced when we have our parent meeting. There is not much we can do but try, and if we think the evaluation is garbage, we will just have to continue working with presumed diagnoses.