3 - Ah, that makes sense. Actually I wasn't even thinking about the thing with the number of players, I just thought that it was interesting. But yeah, it would be nice to make it work with fewer players.
4 - Yeah, understandable. That sounds cool! Personally I'm not a big fantasy fan, so maybe post-apocalyptic (could be useful for Apocalypse World) or some weird horror thing, like hell or some wraith world? Or maybe zoom in and make the map a room or a house, instead of kilometres of wilderness?