Bright Red Innerwear

In Sagume's beat-up picture (post-defeat), the cut in her clothes reveals red underwear This image goes unused in the final version of the game.

The hat pattern is her name

Never had a ribbon in her hair Compare to other (SFW) fanart like post 173401 post 16326 post 5547469

Can you see the broken down shape of Mystia's name in the hat pattern?

The actual spelling is:

For Renko's original appearance in Ghostly Field Club's CD jacket, one can say there never was a ribbon

It only looks like there is one

In Ghostly Field Club's appearance, the collar looks like it could be a ribbon?