Not sure about Cabanas and sit down lunches, but my kids preferred Mickey Bars for dessert at dinner most nights. Even thought they are not listed on the menu as a dessert option, they are always available.
You can order them from room service or for dessert during your evening meal. A Mickey bar was my dessert on 3 of the 5 evening meals on our recent cruise on the Wonder
Never did see a Mickey ice cream sandwich, BUT they make chocolate chip cookies on deck and you take them over to the ice cream station and make your own as many as you like. I know it's not Mickey shaped but tastes good.
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