You get the Witch Doctor after killing Queen Bee, not Wall of Flesh. Also I know it's a little stupid to bring up, but you can actually get different starting NPCs depending on your world seed. Like how 05162020 gives you the Party Girl at the start and For The Worthy gives you the Demolitionist. Also also, a lot of these questions are subjective to different players, so just keep that in mind for making future quests. Other than that, I enjoyed it!