I believe the 2 people on the hillside will vary depending on how you handled the last chapter. Like TTG is supposedly saying, dont erase your saves because it will affect the next season.
If you tell Clem to find Christa and Omid, I bet its them. If you choose one of the other choices (dont trust anyone, or find someone or something along those lines) it won't be them, it will be some new characters. That's my thoughts.
As for who you will play as, I don't think it will be Clem. She isn't as versatile of a character as Lee was. I find it hard to believe they can base a whole season with her as the playable character.