My 5.5 y.o. son has PANDAS and I am an Acupuncturist and nutritionist. The list of supps you have is good, but DHA is very critical to to cognitive function and repair. I recommend Pharmax's Berry high DHA fish oil emulsion which has prebiotics and blueberry in it. It is very pure- as is carlson- but much easier to get down for kids who can;t tolerate the fishy taste or the oilyness of the oil. The other supplement that I have found essential is Behavior Balance DMG by Davinci Labs- the PILLS -NOT LIQUID, this is a formula that has L-carnosine and Dimethyl Glycine which help, L carnosine is an amino acid that boost's immunity and brain function and reduce's inflammation, DMG is a precursor to many amino acids and neurotransmitters that aid in brain and nerve function.
GABA can help with Anxiety and insomnia- bu in high doses can exacerbate, so make sure you are dosing appropriately.
There are, in actuality MANY things you can try. My best advice is to find a good naturopath or DAN who is wiling to think outside the box nd attack the PANDAS rom all angles- the behavioral/neuro angle, the inflammation angle, and the immuno modulatory angle. You need to hit all of these factors to have a truly preventative scenario.
Also, Bach's Rescue Remedy for rages and episodes can be very helpful in the moment. They make a kids one with a base of glycerine.
Good luck, if you have any more questions feel free to ask. I don't want to overwhelm you!