Webby-

She's only tasted ice cream once, and it was strawberry flavored. So that's her favorite.

Huey-

Is boring, just plain ol' vanilla, but if he's feeling fancy, he gets French vanilla.

Dewey-

Dewey would most possibly like to mix every flavor, or just mint chip ice cream.

Louie-

Prefers frozen yogurt, mostly chocolate, or a fruity flavor.