We also saw them at AK. We were there for opening, and there were a ton of characters out - they all came out to the Oasis area of the park for opening time. Then, as we were rushing to the Safari, along with everyone else, we noticed that they had some characters set up at greeting areas through the park. Lilo and Stitch were outside one of the shops as you head into Africa, on your left just before the Welcome to Harambe sign. The greeting area they were in was on the far side of the building - on your left just after you walk past the shop. Since the park had just opened, and most people were so focused on getting to the safari, we were able to see them & get pictures with no wait.