We took our youngest when she was 2. She remembered more than I ever thought she would. For instance, on the next trip (age 4), she asked why we did not go to that Mickey show where he was on the mountain, and the fire was on the water (Fantasmic). I was shocked- We have no pictures of that show, so she could not have remembered it from that.
At that age everything is new, and exciting. Even if they don't get memories, you will every time you look at the photos of your trip. My daughter was in absolute awe during that trip.
Hey- 2 y.o are free for everything too, so what's to lose? The only thing it cost was the air fare, and a few chicken nugget meals, when my oldest was too hungry to share hers.
Have a great trip.