Buckwheat is actually unrelated to wheat. Buckwheat is a seed and does not contain gluten, whereas wheat is a glutenous grain. It seems like hair-splitting, but seed vs grain is apparently quite a difference. Also, buckwheat is a prebiotic, which means it feeds your good bacteria.
I believe buckwheat and oat bran (presumably gluten-free oat bran?) are permitted to be reintroduced while on the strict forum diet after a few weeks, while the other grains are not until much, much later (basically cessation of symptoms, I believe).
The juice pulp crackers are good if you just add some oil and spice them up before dehydrating/baking.