Crack the turkey carcass into several pieces. Place the turkey carcass and legs in a soup kettle with 3 quarts of water and 1 teaspoon salt. Boil for 1 hour. Remove the carcass and legs and cool. Remove the meat from the bones and discard the bones. Reserve the stock and meat. In a heavy dutch oven over medium heat, heat the grease and oil. Add the flour, stirring constantly, and cook until dark golden brown. Add the celery, onion, bell pepper, garlic, and parsley. Cook for 15 to 20 minutes, stirring constantly. Add the okra and sausage and continue cooking for 5 minutes. Add 2 quarts of the turkey stock and 2 quarts of water, Worcestershire sauce, Tabasco sauce, tomatoes, salt, bacon, bay leaves, and cayenne. Simmer, covered, for 2-1/2 to 3 hours, stirring occasionally. Add the turkey meat and simmer for 30 minutes. Just before serving, add the brown sugar and lemon juice. Serve in heated gumbo bowls over rice.