Ok, I decided to fully write my rrat once for all.
I believe that Shiori and FWMC were scouted (scouted here will be used to mean scouted, picked early after auditions, and everything similar) while Nerissa and Biboo went through normal auditions.
1. FWMC
It's evident that there are similarities between their new design and the old one. Blue/red eyes and clothes are the same, they just switched the chest size. This means that either a. they had enough time and power to modify the design to their liking b. the models were designed with them in mind.
We know that fwmc applied before but were rejected. We also know that in december Jap was hired and Omega removed. I theorize when Omega was removed, they went through old applications, someone noticed fwmc, and saw the potential.
2. Shiori
Her design has the same eyes and a very similar hairpin to her first PL. She also has the book theme with her second PL. So, like fwmc, either she influenced the design or it was designed with her in mind.
Ok, here is where it gets interesting. In december 2022 she was super depressed and wanted to quit streaming. I can't find the whole stream though, just a snippet. She drastically reduced her streaming activities, and in may 2023 released her last video.
So, she was depressed enough that I don't believe she could have applied to Holo, she wanted to quit. As Shiori, she said that she applied to Holo, but also said that they saw the "books she wrote" and liked them. My theory is that someone in holo liked her (a talent? someone from the new staff?), so she was contacted and asked to send in an application.
The interesting part is the timing. As I said, in december she was thinking about quitting, in may the design was finished enough that she used the eyes in her last video as video. We know Holo is strict with their schedule, and are ok with low quality models if it means preserving the schedule (Irys, Magni, etc.).
Otoh, Nerissa and Biboo were first designed, and then they looked for someone to play them. They wanted a singer with a bird theme for holotori potential and they wanted a long streamer with a small girl model to stoke the fire under Gura's ass.
What was fwmc's potential is evident. What they liked about Shiori, I don't know. Perhaps it was the fact she was a veteran, and they wanted a tardwrangler for the rest of the unit. Or maybe they liked her asmr? it's not like her channels had huge numbers, asmr aside. The last option is they liked the (unusual) content she did in her first pl, and they wanted a yumejo menhera goth gfe.
Since december is a short month due to holidays, and the time it took for the designs + the time it took Shiori to make her video, we can estimate by early march almost everything about Advent was done and all was needed was to pick the other two girls.
