There have to be dozens of off label uses for Kool-Aid and other food additives, one of the most well known being a temporary hair color. I suspect it could easily be used to color handmade lye soap, particularly the hot process variety. I would rather have Kool-Aid in my soap than crayons or other non-food-grade additives, since what goes on your skin readily gets absorbed in.
I'm going to have to make a test bar on the next small batch I create. In the meantime, Lowes has discontinued carrying the Roebics 100 percent sodium hydroxide crystals, so I would have to purchase future supplies online. I will check the Tractor Supply here in Polk County, but since the area is known for its high domestic consumption of some of the other off label uses for sodium hydroxide, there's some low expectations.
After dyeing the kids hair, and your hair, and the cat's fur, why not try hand-dyeing some white yarn with Kool-Aid for the kids and the cat to enjoy? Or tie-dyed clothing using Kool-Aid and alum? That plain white shirt from the blood donation place could surely use a face-lift.