Zest the lemon with a zester to get 1/2 teaspoon zest. Juice it using a citrus juicer to get 1 tablespoon lemon juice. Set aside.
Place the mini marshmallows, coconut flakes, well-drained mandarin oranges, drained and quartered maraschino cherries, well-drained pineapple tidbits, and halved grapes into a large bowl. Gently stir to combine.
In a large bowl, combine the heavy cream, powdered sugar, salt, and vanilla extract. Whip with a mixer until stiff peaks form. Gently fold in the lemon juice and zest until combined. Fold in the yogurt.
Using a spatula, scoop all the dressing over the salad ingredients. Gently fold until everything is mixed and ingredients are evenly coated in the dressing.
Cover and place in the fridge for 30 minutes to 1 hour before serving. Gently stir before serving.