Take a look at
@RaySharpton post I quoted from last November. He was kid enough to post pictures of the fountain machines and beverage coolers for us!
Sadly the POP beverage selection is pretty limited and they don’t have Coke freestyle machines.

Basically your looking at fountain machines that dispense Coke, Diet Coke, Coke Zero, Sprite, Orange Fanta, Minute Maid Lemonade and Powerade. They also have 4 flavors of Gold Peak Tea, coffee and hot chocolate. Not sure if I’m missing anything else?
When we stayed at the POP in June 2017, we ate at AoA foodcourt a few times because they had Mellow Yellow and I believe Cherry Coke.
For our trip in July, our current plans are taking our refillable mugs with us to HS/Epcot and using the freestyle machines at the Caribbean Beach and/or Riviera Resort (think they have FS machines?) and filling them up, to or from, those parks. We’re a Pepsi family and honestly rarely even drink regular Pepsi, so the added options like Cherry Coke or Mr. Pibb would offer us much needed change.
Does anyone know if there are any places on the Boardwalk that offer Freestyle Machines that can be used with resort mugs. That might also be a nice option and let us visit the boardwalk too! We miss taking that walk from our 2 stays at the Swan Dolphin.