In a small bowl, whisk together 1/4 cup (2 oz.) of the yogurt with the milk. Let sit for 5 minutes to create a buttermilk-like mixutre.
In a mixing bowl, whisk together the remaining yogurt (6 oz.), maple syrup, and coconut oil. Then whisk in the eggs. Once the eggs are incorporated, whisk in the milk-yogurt mixture, vanilla, and cinnamon.
Add the flours, baking powder, baking soda, and salt, and gently fold into the wet ingredients. Add the blueberries and mix in with just a couple folds. Be careful not to overmix - some streaks of flour are okay.
Grease the muffin tin with coconut oil or butter, or line with paper liners. Evenly divide the batter between 12 tins. Cook for 20-22 minutes, or until an inserted toothpick comes out clean.
Let cool in the pan, and then store in an airtight container lined with paper towels for 3-4 days. You can also freeze these muffins for up to 4 months.