I love the frozen lemonade, I saw it in a number of different places. I don't think I had any in AK or MGM. Maybe someone will know about those 2 parks.
It was plentiful in Epcot.
I got it in Toon Town(MK) and at a little stand near tea cups. In Epcot there were a number of different places in WS and I also got one near Test Track. I had about a 3-4 a day habit, loved that stuff!