Would have been a separate game. Three players with choice between 5 characters. Luna, Tess and Tori are the only designed characters.
I haven't really thought much about it but it happens after events of this game. For mechanics, it would have been a little different from this game but didn't work on much.
Yes! Just remember that NPC's don't disappear as long as you are watching them. There's no other way around since player can't stay at one place when interacting with NPC.