Make the coconut caramel sauce: whisk 1/2 cup canned coconut milk, 1 teaspoon vanilla and 1/4 teaspoon sea salt in a small bowl and set aside.
In a small saucepan over medium-high heat combine 1/4 cup brown sugar and 1/8 cup water; bring to a boil and cook, whisking, until it turns golden to light brown (about 5–6 minutes).
Carefully and slowly whisk the reserved coconut milk mixture into the hot sugar (it may seize); continue cooking and whisking until the caramel lightens and thickens, about 5 more minutes, then remove from heat and set aside.
Preheat the oven to 350°F (175°C). Line a 12-cup muffin tin with liners.
In a large bowl whisk together 1 cup all-purpose flour, 1/2 cup cocoa powder, 3/4 teaspoon baking soda, 3/4 teaspoon baking powder, 1/2 teaspoon salt and 1/2 cup sugar.
In a separate bowl combine 1/2 cup coconut milk, 1 egg, 1/4 cup canola oil and 2 teaspoons vanilla; stir lightly and add to the dry ingredients. Beat until combined, then add 1/2 cup hot strong brewed coffee and beat until very smooth.
Portion batter into the prepared muffin cups using a 1/4-cup measure and bake 15–18 minutes, or until a toothpick comes out clean; cool completely on a rack before filling.
Make the frosting: cream 2 sticks softened butter until smooth. With mixer on low add 1 3/4 cups powdered sugar gradually, then beat in 1/4 cup coconut caramel sauce; increase speed and beat 2–3 minutes, scraping bowl, then fold in 1 tablespoon shredded sweetened coconut and 1/4 cup toasted coconut.
Make the nougat filling: melt 2 tablespoons coconut oil in a saucepan over medium heat, add 1/4 cup sugar and 1/4 cup canned coconut milk, stirring until dissolved; bring to a boil and cook 5 minutes, stirring occasionally.
Remove nougat from heat and stir in 3/4 cup marshmallow fluff, 1/8 cup creamy peanut butter and 1 teaspoon vanilla until smooth, then fold in 1/3 cup toasted coconut and 1/3 cup chopped peanuts; set aside.
Make the ganache: place 4 ounces chopped milk chocolate and 1/4 cup coconut milk in a heatproof bowl and gently melt (microwave in 30-second intervals or warm over a double boiler) until smooth.
Assemble cupcakes: use a paring knife to cut a cone-shaped core from each cooled cupcake. Spoon about 1/2–1 teaspoon ganache into the hole, then fill the remainder with the nougat filling, topping with a little more ganache.
Fit the coconut caramel frosting into a pastry bag and pipe a swirl on each cupcake (or spread with a knife). Drizzle remaining ganache over the frosted cupcakes and sprinkle with additional toasted coconut and chopped peanuts; drizzle extra coconut caramel sauce if desired.