As a household with food allergies and all kinds of sensitivities, you have my sympathies!!! Or is it "empathies"?!?!? It really sucks.
I agree with starting with the foods that you know are safe for your family and starting there. If potatoes and rice are safe, then you have a lot of options. ---Believe me, I know it doesn't FEEL like you have options at this point
(((hugs)))