I don't know about the ones *in* the park, but there are also lockers outside of DL to the left of the turnstiles, but more importantly there are BIG lockers outside of the esplanade. You want to be on the DTD side, looking towards the bag check, and you go to your left. There's a picnic area behind some tall thin trees, and there are big lockers. The Jumbo size could have fit a regular suitcase in there...it dwarfed my official-carry-on size bag and the bag I was using as a carryon. So you shouldn't even need the Jumbo size, but I'd go over there instead of trying for the other, probably smaller, lockers.
Have fun! And remember that if you have to go through bag check with it to get to the lockers, you'll have to open things up for the CMs.