The nun and the idol are not unlockable at any certain point in this build, its a demo which only includes the main girl, you can still obtain npc scenes but saves arent that useful because the gallery system isn't implemented yet. I'd advise to just play it all out, you will unlock about all the scenes in about an hour or 2. A tip: Once you've made enough money(Or cheated it in). Focus on getting your chaos higher but not high enough where you'll get fired. Getting higher chaos affects npcs to where you can unlock their scenes.