What sort of plot are going to have? Fruits Basket is rather "slice of life" in nature and conflicts, so is there anything you're going to do to spice things up? It's hard to see slice of life roleplays take off in advanced (for example) because of the slow pace that involves and the conflicts being mostly personal. With the use of an all OC cast, are you going to narrow the focus down to any sort of select people, since including everyone (13 people who can transform) might be a bit ambitious and cluttered?