1. Preheat the oven to 425° F and cover a large baking sheet with parchment paper.
2. Add the sweet potatoes to a large bowl and drizzle the melted coconut oil over the top; gently toss to coat with the oil. Spread the potatoes on the baking sheet and place in the oven for 10 minutes, until the potatoes begin to soften.
3. In the same bowl, toss the carrots, Brussels sprouts, onion, and pepper with the paprika and garlic powder. Remove the potatoes from the oven, and with a spatula, flip the potatoes and move them toward the side to make room for the vegetables. Add the vegetables to the pan and liberally season the vegetables and the potatoes with salt and pepper; place in the oven for 15 minutes.
4. While the vegetables cook, make the tarragon butter. In a small saucepan over medium heat, add the butter and shallot. Cook, stirring frequently, until the shallot is translucent. Add the garlic and stir for another minute. Reduce heat to low and add the remaining ingredients; stir to combine then remove from the heat and set aside.
5. Remove the vegetables from the oven, and gently toss the vegetables and potatoes. Make room on the pan by pushing the potatoes and vegetables toward the side. Add the sausage and the shrimp in two lines. Place in the oven for 7-9 minutes, until the shrimp turn pink.
6. Remove from the oven, drizzle ¾ of the tarragon butter over the shrimp and the rest over the vegetables. Gently toss all ingredients on the pan to ensure even coating and even cooking. Season the shrimp and the vegetables with salt and pepper and place back in the oven for about 3 minutes. Remove from the oven, gently toss again and serve immediately. If desired, top with the fresh chopped parsley and serve with lemon wedges and optional sauces.