All the girls will be there, the normal graphics come on when you aren't playing as Lilly. But I need to make more objects first, redraw all the girls, etc.
Nifty concept. If I may make a suggestion, have you considered a mechanic for smell as well as hearing?
My thoughts: some rooms have strong smells associated with them: "I love the smell of tea" for Lilly's room, for example, or "I never really liked the smell of medicine" for the Nurse's office, or even "Ugh! Paint fumes!" for the art room. These strong smells could be represented by turning the background a different color (which obviously is not what Lilly experiences, but the existing graphics are already an attempt to translate her experience into sight). This allows for a limited form of landmarking ability, though most rooms probably shouldn't have strong smells worth pointing out.
In addition, some objects also have distinctive (though weaker) scents. If there isn't an overpowering scent in the room, then as Lilly comes near scented objects, she begins to smell them: the background begins to change color again (possibly matching a room associated with the scent). Smell can't directly indicate the direction of an object, nor does it necessarily indicate exactly what the object is, but it does get stronger (to a limited degree) as Lilly gets closer. "Huh? Do I smell paint?" might indicate that Rin's latest work-in-progress is nearby, or it might indicate Rin herself. "Someone has clearly been exercising" could be Emi, or some other member of the track team, or just a pile of laundry. "Grapes? Why do I smell grapes?" might indicate Hisao and his "cologne".
The idea isn't really to make the game easier, though some objects (especially objects hidden behind or under things) might be easier to smell than they are to see. Some of those could even be items that Lilly herself doesn't need, but another character might.
I've considered adding smell (it would be easy to add them), I just don't have anything that uses it yet. Those are some good suggestions, though, and I try to make playing as Lilly easier just because it's so hard to play as her.
In most cases, other characters can go to the same areas that Lilly can, so you can just change which character you're playing to see what's near Lilly, but there are times when only one girl can get to a particular area.
