I am going to assume some tHinGs about the HoO characters.
Nico: He likes German chocolate
Leo: He likes Chili.
Percy: Has multiple stuffed animals/plushies.
Annabeth: She keeps different types of weapons in her room.
Piper: Her favorite flowers are roses.
Jason: He secretly goes on dates with his brick.
Hazel: Has a flat screen TV.
Frank: Shares his stuffed animals/plushies with Percy.
Reyna: Instead of writing her full name she writes RARA.