So the SM manga references is Saito's fault.
Anime Rei is his creation with Sato, I think Chiho is the one who is fond of the manga of SM in the first place.
Saito has similar ideas with Takeuchi...which I think is why he picked her in the first place.
So the Revolutionary Girl Utena was originally conceptualized by Ikuhara with Michiru as the MC, the manga and anime of Utena did end up with Anthy as the one surviving, so that idea did actually push through.
If you want CLAMP to make a Sailor Moon spin-off don't expect a good portrayal of Mamoru because they don't like Mamoru's character in the anime or manga unless they have changed their views since then or it is Naoko writing the script.