Considering that the 55$ are only good at Palo and not at Remy or Enchantee I would guess that it will be Palo only.
If they made it available at Mike & Sully‘s which is not adult only, they would have to give it to Platinum kids as well and they for sure wouldn’t want to do that.
I have actually been wondering how the CC makeup of these cruises is going to be and am thinking that Pearl, Platinum and Gold cruisers might be a rare species at least for the he first couple of years (besides Maiden Voyage). So there might be a real advantage when booking special stuff. But then I look at the sheer amount of concierge cabins and think they will gobble up all specialty dining anyway…