Watching Oshi no Ko season 3 episode 8

I watched the Oshi no Ko episode 8 on the season 3. Ruby obviously got angry with Aqua and got mad at him because he tipped off at Ai. While she was pushing him to the wall, her white star became a black star on her left eye. In the last episode, the white star was on her right eye. I didn't get why the eye was changed from the right to the left in this episode, but at least changing from white to black seemed to show that she was disappointed with Aqua or anyone and resolved more revenge.

For the rest of this entire episode was almost about the new film the Director Gotanda made. Ai affected so many people surrounding her even him and made a script for that, and then Kaburagi decided to make it. I wasn't sure how Kaburagi decided casts, though. From an watcher's perspective, it's obvious, but if I would need to think logically, B-komachi is the one for B-komachi's casts, Akane and Frill are those for talented idols, Aqua is obvious. I don't know Melt and Yura. It needs a capability to accept something dark and made it and he said he is the only one who can make but forgot why he thinks that way. What was his past?