So my dungeon in My Main World is a bad dungeon. This happens when a cave interrups the dungeon and the rest of the dungeon dissapears because of the cave. Now i am trying to get a truffle so i can get autohamer and make shroomite bars and then hoverboard and bla bla bla. I was recently told that u must have all the npc's for the truffle to spawn. Now i need the Mechanic and the Angler. I will get the angler after my Mechanic but i am just asking, Will the mechanic spawn in the stairs leading down to the main part of the dungeon???
You don't need all NPCs for truffle. Just an overworld(above level) mushroom biome with a house in it.
The mechanic will only spawn in the dungeon after a certain depths in the underground, so she won't spawn anywhere near the entrance because that's too near the surface. Try making a new world for her or dig through the ruined dungeon and see if you can get lucky.
Lastly, seeing as you have a faulty dungeon, are you on mobile by any chance? If so, you won't have the Angler just yet.