POUR 2 cups milk into large bowl. Add dry pudding mixes and juice. Beat with wire whisk 2 min. or until well blended. (Mixture will be thick.)
SPREAD 1-1/2 cups of the pudding onto bottom of crust; set aside. Add half of the whipped topping to remaining pudding; stir gently until well blended. Spread over pudding layer in crust. Place 2 cups of the marshmallows in large microwaveable bowl. Add 2 Tbsp. milk; stir. Microwave on HIGH 1-1/2 min. or until marshmallows are completely melted, stirring after 1 min. Stir until well blended. Refrigerate 15 min. or until cooled. Gently stir in whipped topping; spread over pudding mixture.
REFRIGERATE 3 hours or until set. Top with the remaining 1/2 cup marshmallows just before serving. Store leftover pie in refrigerator.