Combine buckwheat, chia seeds, 1 1/2 teaspoons coconut, flax seed meal, cinnamon, and vanilla powder in a jar; stir until well mixed. Stir in milk; cover. Place in the refrigerator, 8 hours to overnight.
Stir buckwheat mixture. Heat in the microwave for 30 seconds. Stir in mixed berries, remaining coconut, and agave.