I think it would be really funny if the mother and daughter were actually "normal" and non-malicious or scheming, but just really weird instead so all this awful stuff stuff we are seeing as readers is just paranoia and we'd all look silly by the end of everything.
Used items? You DID NOT beat the game. Exploits? DID NOT beat the game. Knew boss information beforehand? You DID NOT beat the game. Had help fighting the boss, NPC or not? You DID NOT beat the game.