Buffalo Sauce: Melt coconut oil in small saucepan over low heat. Whisk in hot sauce, brown sugar, and vinegar until combined. Remove from heat and cover to keep warm; set aside.
For the Cauliflower: Line platter with multiple layers of paper towels. Add oil to large Dutch (about 6 quart and cast iron works great) oven until it measures about 1 1/2 inches deep and heat over medium-high heat to 400 degrees. While oil heats, combine cornstarch, cornmeal, 1/2 teaspoon salt and 1/4 teaspoon pepper in small bowl. Whisk coconut milk and hot sauce together in large bowl. Add cauliflower; toss to coat well. Sprinkle cornstarch mixture over cauliflower; fold with rubber spatula until thoroughly coated.
Fry half of cauliflower, adding 1 or 2 pieces to oil at a time, until golden and crisp, gently stirring as needed to prevent pieces from sticking together, about 3 minutes. Using slotted spoon, transfer fried cauliflower to the paper-lined platter.
Return oil to 400 degrees and repeat with remaining cauliflower. Transfer 1/2 cup sauce to clean large bowl, add fried cauliflower and gently toss to coat. Serve immediately with dressing and remaining sauce.