OK, so we all know that one of the things that makes dDisney special is their desire to deliver top notch customer service. I've worked for several companies who send managers to disney to learn what true customer service is. I think they will be accommodating. Also, a restaurant such as BOG isn't just a meal, it's an experience in and of itself. To forego the experience, because the menu isn't perfect for everyone in the party is hard to accept.
I would avoid the "special request" route. My wife and two of my daughters can't eat gluten- so am very used to Disneys accommodations. However, they are limited to what they can do. They'll have allergan free products, but your child may like these no more than anything else.
I'd say that if he'll eat chicken with ranch then get some sealed packages and keep them in your purse for the duration of the trip!
On a side note- and please don't take this as parenting advise, just a sharing of our disney experiences....The themeing of some of the Disney restraunts have helped us convice our children to eat things there that we had not had luck getting them to try at home. "This is what Belle ate growing up" might go a long way to get them to try something new.
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