Skip the kidgest, use the capsule powders, you can sprinkle them directly on whatever you're eating (they're pretty tasteless, and you need stronger than the kidgest stuff).
Ditto. Their KidsDigest is very weak and doesn't have DPP-IV activity or phenol tolerance enzymes.
If you wanted to go with Enzymedica, I would start a kid on Digest Basic, which is very gentle and low in proteases. Then move to Digest, then Digest Gold which is the strongest. Going very carefully. Or can do Gastro instead after trying a bottle of Basic. But you would have to add their Gluten Ease for DPP-IV (starting with 1/3 capsule with one meal and gradually stepping up). Digest Gold reportedly has some DPP-IV for gluten and casein but not much.
I do not think Enzymedica has a high xylanase enzyme product for phenols and sals like Houston's No Fenol, Zy Carb or TriEnza, they are unique.