Hello,
My final game Magic Ring will be based on fictional city of Japan so I'm learning more about Japanese culture. I can't say I have deep knowledge of it but it's better than what I had some years ago.
To be honest, You Rei? one is a coincidence. These are just made up names that match pronunciation of ghost names. Since this game is taking inspiration from Phasmophobia some ghost are just how hot girl version of those ghosts will look.
For a long time, I had assumption was Tall Lady looked like fashion model from Mr. Ito's horror collection. This tall lady is not the original Hasshaku-sama but an evil clone of a character from future game. I have made the real Hasshaku-sama for an alternate version of this game that will not be released publicly or not until Magic Ring is published.
I haven't visited Japan yet but I'm planning to in future.
Regina is my favorite character too. That's why she has control over events happening in this game's universe. Unfortunately I have no plans for her sex animation in this game. I might do that for Magic Ring but I have to see what's DLSite's stand of such content.