Alicia and Welkin, the stars of Valkyria Chronicles, will return in Valkyria Chronicles 2. After the last war, Alicia became a baker and Welkin stuck with her. Both of them can aid Avan as playable characters if you can get them to join your platoon.
Fan service? You bet! And Sega has even more of that. Lamarre from the Valkyria Chronicles anime and two characters from the Valkyria Chronicles: Wish Your Smile comic, Mitnz and Julius, are in the game too.