I've always thought it was a little strange how Mika Kayama only appears in the anime, even though she's mentioned on Shingo's design page in the Materials Collection. This makes me think Naoko came up with the character and was going to include her in the manga, but then never got around to working her in. It would have been nice to see her show up, if only because it would have helped flesh out Shingo a little bit.
I'd also love it if Yuuchirou were in the manga (but as a "big brother" type character for Rei, not as a potential love interest).
I'd also love it if Yuuchirou were in the manga (but as a "big brother" type character for Rei, not as a potential love interest).