I haven't picked up my copy of the game yet, but yes, there are 108 stars. Not all of them are usable in combat though.
The 108 is kind of this series' "thing". The original was loosely based off a great novel called Outlaws of the Marsh. In it, the 36 Heavenly and 72 Earthly Fiends all come together to form an army. Thus, the 108 Stars of Destiny.
I have it on good authority; if you type Google into Google, you can break the internet. So please, no one try it, even for a joke. ~ Jen, The I.T. Crowd
there's only 1 member who can't be used at all in battles. And that is Moana. Then there are 14 support characters who you dont directly use in battles. You just put them there and they give you some extra effect like healing you at the end of the turn. All the others are totally usable. even characters who are not supposed to fight (like the elder of your village, or your "mother", or some dancers, everyone fights)