Oven tuna croquettes

I looked in my recipe box and I found the ingredients list for the croquettes I mentioned in an earlier post, so I will post the recipe as best I can remember how to make it

1 cup cooked brown rice
1 T butter
2 T whole grain flour
1/2 C milk
1 can tuna
2 T minced onion
2 T lemon juice
1/2 tsp salt
1/3 C Butter
1 egg
3 T milk
1 1/2 C whole grain bread crumbs

Melt 1 T butter, add flour to make a paste. Add 1/2 cup milk and cook over low heat until it thickens into a white sauce.
Mix rice, tuna, onion, lemon juice, salt, and white sauce in a bowl. Form into balls.

Melt 1/3 cup butter and place in shallow bowl. Mix egg and 3 T milk and place in another shallow bowl. Place bread crumbs in a flat dish like a pie plate.

Roll balls in egg mixture, crumbs, butter, then crumbs again and place on baking dish. Bake at 350 until outside is crisp and they are heated through. (I can't remember how long they take, and I put 350 because that is sort of a default oven temperature.)

I'm thinking these would make a good portable snack for pre- workout etc. Since I am trying to cut way down on gluten, I will try crushing up my gluten free crackers for crumbs, and I may only dip them in egg and then crumbs. I could also try oats or crushed nuts. Anyone else have any ideas for a crumb substitute?

Allison