My DD's third trip was when she was just a few weeks shy of two. Hands down, hugging characters was her favorite thing that trip. But just a couple months earlier, you would have thought Anna and Elsa were terrifying monsters, the way she reacted to meeting them. So, point is, toddlers are unpredictable and not all alike, so check in with your 2-year-old often to see what he's enjoying. Because you have a number of character meals set, I'd recommend trying to do at least one character meet & greet first so that you will give your DS a chance to warm up and see if he likes them or is afraid of them, rather than going into a meal and finding out he hates them at that point (hopefully he won't).
Otherwise, in all 3 trips (14 months, 21 months, 23 months), DD has consistently loved all rides and not cared for many shows. And I think just about every 2-year-old has It's a Small World high on their list. Also, especially since you'll be going in hot June, make sure to know where air-conditioned rest and/or play areas are. Inside the Dumbo tent is good for getting some energy out and the baby care centers are good just to cool down and relax for a bit.
Have a great time!