Preheat oven to 400 degrees F. Line a 6-cavity jumbo muffin pan with paper liners.
Add all-purpose flour, baking soda, ground cinnamon, ground nutmeg, ground ginger, and fine sea salt to a small mixing bowl. Whisk to combine. Set aside.
Add vegetable oil, applesauce, granulated sugar, and light brown sugar to large mixing bowl. Whisk until the mixture is smooth.
Add pumpkin puree and banana puree to sugar mixture. Whisk to combine.
Add melted chocolate to pumpkin mixture. Whisk to combine.
Add lightly beaten eggs to pumpkin mixture. Whisk until completely incorporated.
Add milk to pumpkin mixture. Whisk until completely incorporated.
Add flour mixture to pumpkin mixture. Fold in gently with a large spatula.
Divide pumpkin muffin batter between jumbo muffin liners.
Sprinkle streusel over muffin batter.
Bake muffins in preheated oven for 28-32 minutes, or until a toothpick inserted in the center of a muffin comes out clean. Remove muffin pan from oven and place on wire rack to cool for several minutes. Remove muffins from pan and cool completely.