Count me in on this one! I'll see if my girlfriend wants to come as usual. As for respawns, I think you could take a good example from video games that have a respawn system for common enemies; It'd be a whole lot easier to plot out with maps and whatnot, but in terms of a spawning system... For zombies, I would have them spawn in waves, so that it is more a full on zerg than two or three zombies shambling down a hallway. For the other people, it mainly depends on how you want the game to play out.