I've noticed that Miri and Nao sometimes have what looks like a claw mark by one of the eyes, but other times doesn't. This a hint they are both Myths as well (Nao might well be, but a valley girl Myth seems a bit...odd), just a fun little addition, or what?
Having played through as much as possible, I would say Okami or Suzu are the most guarded initially. Suzu makes sense, but a little surprised at Okami. Maybe she's just soured because of Ichiro? Friendliest (outside of the twins) is either Miko or Nagisa. Word of the day is "chickle" (even if it doesn't exist!), and most adorable is Perrine!