Seems like a good time to make a thread for this since new characters are being introduced out of the whazoo at this point.
Agitha has been confirmed as a playable character. Yes, THIS Agitha, from Twilight Princess:
She uses her parasol to attack and can call on insects.
Another new playable character is Lana, a brand new character and most probably the blue haired girl shown on the box art. She's a witch. She uses a spell book to fight and uses barriers to brush enemies out of the way.
Midna and Agitha have seemed like pretty far-out choices. It makes the prospect of Tingle all the more frightening.