Put all Liquid in a large stock pot and bring to boil.
Saute onion, celery, bell pepper, and garlic in bacon grease or a couple tbsp of oil about 5 minutes. Add to liquid with okra, bay leaf and bouillon cube. Cook about 1 hour on medium heat.
While liquid is cooking, make a roux with the 3/4 c. flour and bacon grease/oil mixture cooking until dark brown in color. Add to liquid. Stir in completely and add shrimp and crabmeat. Cook over med low heat in uncovered pot for about another 1/2 hour. Add oysters and their liquid and cook until the edges of the oyster start to curl. Remove bay leaves and top with green onion. Can be served over rice or alone.