1. In bowl, with electric mixer on low, combine whipped-topping mix and cold milk. Increase speed to high and beat 4 minutes.
2. In large bowl, whisk together fat-free sweetened condensed milk, lemon juice, and grated lemon peel. Whisk in whipped topping. Blend in yellow food coloring.
3. Pour mixture into a reduced-fat graham-crumb crust and freeze. Flip the plastic cover from packaging for a lid. Garnish with Cool Whip and fruit slices.