If you haven't done it yet, hit the dojo mode. It's done with Jago and some info has changed through the seasons (juggles are breakable now) but it is a phenomenal starting point and breakdown of about 85% of the stuff you'll use in the game. Otherwise, take sneaky tortoise up. He's good people. (Yes, I said it.)
Also if you're wanting to piecemeal the cast, Maya's on sale for a dollar and Aganos was a few days ago. KI sales seem to be happening.
They are. And to answer someone's question from earlier, Shadows are and aren't a good mimic of player's style. This is simply because it takes a LOOOOOOOOOT of records to really start mapping down your exact style and nuance and the AI naturally has some difficulty with some, usually more set-up heavy, characters and really just making them work, much less mimicing their player's style.
Well considering I made my Shadows when all I knew to do was Heavies 24/7, very accurate lol. I'm sure it's good though.