Thank you so much for your input and suggestions. Having people who are willing to "listen" to the whole story of what's going on and tell us that we are not alone is refreshing and so deeply appreciated. Thank you from the bottom of my heart.
In trying to outline some semblance of a plan amid all of this uncertainty, the points that jump out at me as next steps are: investigate possibility of mold in our house, find a PANS/PANDAS-friendly doctor, and advocate for a comprehensive panel of tests. I have seen elsewhere in these Forums a reference to the "Cunningham Panel" - is that the be