Drain the pineapple juice from the crushed pineapple pieces. Combine the pudding with the pineapple juice and whisk until smooth. Stir in the pineapple, coconut, and mini marshmallows. Now, fold in the thawed Coolwhip and thoroughly combine the ingredients. Chill for at least 2 hours, 4 hours preferably. Sprinkle the chopped pecans on top and garnish with a Maraschino cherry.