Combine dry pudding mix, dry Crystal Light Lemonade drink mix and the sugar substitute sweetener. Add milk and beat with a wire whisk until mixture is thickened. Fold in the whipped topping. Spoon into the graham crusts. Cover and chill at least 3 hours or freeze for 8 hours.
Options: Substitute other flavored dry drink mixes for the Cyrstal Light Lemonade (using 1.5 ounces measurement) such as Koolaid flavors, Propel, etc. Just experiment and have fun! If you don't need sugar free make it without sugar free ingredients. I'm considering substituting dry Jello crystals for the Crystal Light and see what happens.