Well, going through the Princesses....All of these have meet and greets: Pocahontas, Elsa, Anna, Cinderella, Snow White, Belle, Ariel, Rapunzel, Jasmine, Mulan, Tiana, Merida, Sofia, and Elena. I'm not sure if Aurora is still meeting in France or anywhere else, but she can still be found at Akershus, CRT, and the Perfectly Princess Tea Party. I think that is all of the Princesses... except for Moana. Granted, she might not yet be considered a "Princess" by Disney, I don't know, but she should still have a place there, especially given how new and popular she is.
I think Disney puts perhaps a bit too much focus on some of the original princesses: Cinderella, Aurora, Snow White, and Ariel. They should absolutely have a place there, I wish it wasn't essentially the same characters at CRT and Akershus (with the exception of swapping Cinderella for Belle) and that they'd incorporate some of the newer Princesses into more things. I know my daughter will be happy to meet all of the princesses, but the older ones just don't have the same appeal as Elsa, Anna, Moana, Merida, and Rapunzel. I would bet a lot of money that the Perfectly Princess Tea Party would be harder to get than the combined difficulty of Be Our Guest dinner, Bibbidi Bobbidi Boutique, and a Flight of Passage fast pass IF they put Elsa there. It just baffles me that they seem to have missed out on great marketing opportunities concerning the new princesses.