Hi Heather. I'm sorry that your little one has these allergy problems, but the good news is that you caught it early. I'd suggest the magazine Living Without for really good advice and recipes; their website is http://www.livingwithout.com/
I'd also avoid rye and buy only oats that are labeled "Gluten-free", such as Bob's Red Mill sells.
One problem that just recently cropped up, which you have probably heard about, is arsenic in all rice. The article in Consumer's Report magazine goes into detail. I would avoid all rice, rice flour, products with rice-syrup for sweetener on the label, until such time as the FDA puts limits on the amount of arsenic acceptable.
My suggestion for cereals for your little one is Cream of Buckwheat, gf oats and quinoa. f you bake, many of the gf cooking/baking websites are giving recipes containing almond flour/meal and coconut; sorghum is a favorite of mine. This elimination of rice has made baking edible foods difficult. However, wheat is much higher in carbs than almond meal and coconut.
Also beware of everything in a restaurant; wheat is in so many places you wouldn't suspect, such as French Fries. Of course that does leave vegetables, fruit, meat, fish, poultry, etc. Best of luck to you!