Keep the Songbirds, but what they need is a rival band to serve as foils/drama to make the quest interesting. The way the songbirds are structured doesn't really add any conflict or provide any real decent mechanics; they need someone to play off of to make them come alive some. Have them go against the Blackbirds or something, who try to cheat and sabotage them. This event sucked because it was japanese cliche x 2, idol singers and cute ghost girls. If you are going to do this, at least add conflict to spice it up.