1. The tags and the artist's comment describes that the little girl is Koa's little sister who is introduced in another series (maybe some fanfiction), and has the name (I'm guessing half-nickname) Kokoa. [Ko means 'small' in Japanese, so it's Little-Little devil.]
2. Patche took Koa sister's car from the JR terminal to arrive at Scarlet Devil Mansion.
3. Artist's comment : Huh? Year of the tiger? Ah... Well, please forgive me by Kokoa's little present. It looks like a tiger!
well yes, the fact that its been depicted as apparently being on fire or something in every single one of the last 8 pictures is why its worrying, though