In large bowl, whisk together all-purpose and whole wheat flours, oat bran, baking powder, baking soda, and salt; whisk in sunflower and pumpkin seeds.
In separate bowl, whisk granulated sugar, brown sugar and orange rind; whisk in eggs and buttermilk. Whisk in butter until combined; stir in flour mixture in 2 additions just until combined. Stir in cranberries. Spoon into 12 greased muffin cups.
TOPPPING: Sprinkle with oat bran, sunflower seeds, and pumpkin seeds.
Bake in 375F oven until cake tester inserted in center comes out clean, about 25 minutes. Let cool in pan on rack.