I suggest making your own cookie dough instead so you have more control over the ingredients. Make the following changes to any classic sugar cookie recipe:
Replace the butter with a blend of 50/50 light butter and fat free half and half
Replace the all purpose flour with white (not traditional) whole wheat flour
Replace the eggs with 100% egg whites
As for the whip cream and sugar replace that with fat free whipped topping. You could also try mixing a sugar free pudding mix with the whipped topping. I think a cheese cake or white chocolate one would be fantastic with this recipe.
As far as great kid recipes go, try the cook book Fast Food Fix by Devin Alexander. This has copy cat recipes for a myriad of classic fast food recipes done in far healthier and more diet friendly ways. Burgers, fries, chicken, pizza, pasta and much more. They will probably love it.