GOD i just finished this after work and needless to say I adore it. As always your prose is phenomenal (and such an inspiration). I actually figured out the twist relatively early, but it didn't hurt my enjoyment of the story at all.
The toxicity of love between Medea and Rosette is SO intriguing. I think it's a wonderful continuation of the story, and I'm so glad you decided to focus on them, as I definitely agree the Lonely LIs' stories feel very... complete? And I like the little nod that in the end they're just aspects of Medea and her all-consuming love for Rosette. All in all, such a lovely addition to the story and will definitely be encouraging people to read it (after getting them to read Lonely)
(ALSO YUZUKI'S OST IS STELLAR AS ALWAYS)