Whose Hellos Are These, Anyway?

In a bizarre twist of fate, you find yourself in a city where every greeting is a puzzle. As a professional 'Hello Investigator,' your task is to navigate a labyrinth of social interactions, decoding peculiar greetings that hold secrets about the city's eccentric inhabitants. Each character has their own unique style of saying hello, and their greetings unlock clues to unravel the looming mystery of disappearing greetings—a case that has left the city in a state of confusion. Can you crack the code of the infamous Hello Society and restore normalcy before all meaningful communication vanishes?