The game is out, and so is the characters:
Shane Walsh
Greg - Original Character
Lori Grimes
Kara - Original Character
Summer's Dad - Original Character
Summer's Mom - Original Character
Summer - Original Character
Carl Grimes
Ed "Trucker" - Original Character
Bob - Original Character
Davey - Original Character
T-Dog
Jade - Original Character
Presumeably Glenn
It appears to be canon to the TV-Series.
I'll update when i get longer into the game.