I can't speak to Y&Y since I stick strictly to Disney owned food establishments because they're the only ones Disney gives me any info on.
AK is an extremely frustrating park for me food-wise. The only places in the park to get GFCF meals seem to be all grouped together on one side of the park (besides Tusker House). Well, what if we're on the other side when we're hungry? I'm one of those people who do detailed touring plans for trip and I've got my second day at AK set up with this exact situation. We're basically going to skip lunch that day and chow down on some fruit (Harambe has a beautiful selection of fresh fruit) and then get another snack maybe 1.5 hours later followed by an early-ish dinner. It really is frustrating.
Here's what I've got on my list for my August trip for GFCF foods at AK.
Restaurantosaurus: allergy chicken tenders, french fries, hamburgers on Ener-G buns, hot dogs on Ener-G buns, Silk soy milk, French Meadow brownies, Enjoy Life cookies
Dino Bites: (right by Restaurantosaurus so probably available through them as well): Tofutti and Rice Dream ice cream
Dino Diner: Frozen Coke
TriloBites: Turkey Legs
Turkey Wagon (Discovery Island): Turkey Legs
Pizzafari: Silk Soy Milk, French Meadow Brownies, Enjoy Life Cookies
Outdoor Food Carts: popcorn, Lays chips, frozen strawberry bar
Kusafari Bakery: French Meadow brownies, Enjoy Life cookies
Harambe Fruit Market: assorted fresh fruit, Lays chips
Drinkwallah: assorted fresh fruit, Frozen Coke