The Pineapple Lanai is a must when I'm at Disney! They offer your traditional dole whip but they also do specialty flavors. We had just missed the Key Lime pie flavor, which still makes me sad, but I decided to do a mix of their regular lime and the vanilla. That came out so good and I highly recommend it.
If you need a midday break while you're at Magic Kingdom, or just a down day activity, I always recommend hopping on the monorail at Magic Kingdom and taking a spin around the monorail resorts. The Contemporary Resort has great shopping! Currently the monorail is not stopping at the Polynesian resort due to construction, but you can get off at the TTC and walk to the Polynesian. You can walk back to the TTC and hop a monorail over to the Grand Floridian where you can grab some bath bombs at Basin. Mobile order an iced coffee from Gasparilla Island Grill and it will be ready when you're done shopping!