Honestly, I don't really think Cirno is dumb. I think most of the problems would be fixed by having Eirin give her some stimulants.
Last time Eirin gave a fairy stimulants, she had to end the Cretaceous to set things right.
You already take the paper at your place anyway, right, Cirno?"Rumors"Then what did you come here for, Shameimaru?Sorryyy!Good grief!...actually, I came to restock on interesting rumors.Mmm, well...Ohhh!