Boil the lobster tail in ½ cup of the wine in a saucepan. Reduce the heat. Simmer, covered, for 10 minutes. Drain and peel the lobster, reserving 2 tablespoons of the lobster stock. Cut the lobster into medallions and keep warm.
Spread the butter in a baking dish. Arrange the fish in the buttered dish. Pour the remaining ¼ cup wine over the fish and sprinkle with ¼ of the green onions. Bake at 400 degrees for 15 minutes. Drain the baking liquid into a saucepan. Reduce the oven temperature to 300 degrees. Turn over the fish and sprinkle with salt, pepper, onion powder and garlic powder. Return to the oven. Bake for 5 minutes.
Add the reserved lobster stock to the baking liquid. Stir in the cream. Boil until the mixture is reduced to a sauce consistency. Add the lobster and corn. Stir in the remaining green onions. Pour over the flounder fillets.