Box describes them as "light ice cream." Is that what the version in the parks is made with?
I'm not sure, but it sounds the same. The park version says it has "Milk Fat and Non Fat Milk" in it. Below is the store version's ingredients.
https://i2.wp.com/**************.net/wp-content/uploads/2019/01/mickeybar3.png?resize=550,305&ssl=1
and here is the park version (courtesy of bumbershoot)
https://www.disboards.com/threads/mickey-bar-ingredients.2032894/
Milkfat (not even cream)
and nonfat milk,
coating, sugar, chocolate, coconut oil
dutch processed cocoa powder
soybean oil, cocoa butter, dairy oil
soy lecithin, artificial flavors, sugar,
corn syrup (the problem in our household),
whey powder,
stabilizer
(mono-diglycerides, cellulose gum
locust bean gum, calcium sulfate
polysorbate 80 carrageenan),
natural and artificial flavor,
turmeric extract color,
annatto color