Heat 3 tablespoons canola oil in a large Dutch oven over medium-high. Add sausage, and cook, stirring occasionally, until browned, 4 to 5 minutes. Transfer sausage to a medium bowl using a slotted spoon, reserving drippings in Dutch oven. Add onion to drippings in Dutch oven, and cook, stirring occasionally, until onion begins to soften, 3 to 4 minutes. Add bell pepper and celery; cook, stirring occasionally, until bell pepper begins to soften, about 3 minutes. Add garlic, and cook, stirring constantly, until fragrant, about 1 minute. Stir in rice, Creole seasoning, dried shrimp, 2 teaspoons salt, and 3/4 teaspoon black pepper; cook, stirring constantly, until well combined, about 10 seconds.

Add tomato paste to Dutch oven; cook, stirring constantly, until rice is evenly coated, about 1 minute. Stir in chicken stock, crushed tomatoes, hot sauce, and reserved sausage. Bring to a simmer over medium-high; cover, and reduce heat to medium-low. Cook, undisturbed, until all liquid is absorbed and rice is tender, about 20 minutes.

Sprinkle shrimp with remaining 1/2 teaspoon salt and remaining 1/4 teaspoon black pepper. Heat remaining 1 tablespoon oil in a large skillet over medium-high. Working in batches if needed, cook shrimp, turning once, until just opaque, about 1 minute and 30 seconds per side.

Add cooked shrimp, dill, parsley, tarragon (if using), and lemon juice to rice mixture in Dutch oven; stir and fluff rice to combine. Garnish with sliced scallions, and serve hot.