Question. Does this contain the story of the original and if so are there story additions to the original characters.
P4AU's story contains none of P4A's story. Different games, different stories, albeit it only a few in-universe days apart of each other.
This isn't true. P4AU's story is a straight up, 15 hour sequel to the first game. However, P4AU also contains the entirety of P4A's story with every separate character chapter, as the DLC: Episode P4A.