Heat 1 tablespoon of the canola oil in a large Dutch oven over medium-high heat. Add the andouille and cook until browned, about 5 minutes; remove to a plate, leaving fat behind.
Reduce the heat to medium; add the remaining 3 tablespoons oil and the flour, and cook, stirring, until the roux reaches a light blond color, 5 to 6 minutes.
Add the onions, peppers and celery, and cook until the vegetables have softened, about 5 minutes.
Add the garlic powder, seafood seasoning, chipotle powder and thyme; cook for 1 minute.
Add the tomatoes, chicken stock and the cooked sausage, stirring until the roux is dissolved. Bring to a boil, then reduce to a simmer, and cook for 45 minutes to allow the flavors to develop. Season with salt and pepper to taste.
Ten minutes before serving, add the crabmeat, lobster and shrimp. Cook until the shrimp and lobster are pink and cooked through.
Serve over basmati rice.