I can imagine that there are some designs that are already designed or at least in half-finished phase when it's revealed to the talents before debut so that they can figure out their own name or something like that. Like say, Luxiem probably have planned to be like 'here's mafia guy, here's demonic looking asshole, here's some purple guy, along with a fox detective and glasses wearing blue boy. Y'all can figure out the name yourself' or something like it.
Yep. Oliver Evan's design was last seen on an old Nijisanji JP audition notice on JP news website PR Times, specifically for
an JP audition that happened at the end of 2019. It's likely assumed that only Oliver in Eden-Gumi to be the one with repurposed old designs while the rest like Axia (grad), Leos Vincent, Nipple boy Lauren Iroas and Lain Paterson is designed after audition or something like that.
And it's not ending there either. From that post I linked, they reused two old designs for Ha Yun and Lee On (grad) of Ex-KR as well, and they still probably unknown number of unused models that they keep around from their old auditions and such.
One of the first Sanbaka interaction I ever remember watching is when the three of them is doing "Mystery Hotpot Challenge" where Nijistaff casually created culinary catastrophe against the trio by adding unusual to downright 'it's not supposed to be in there' ingredients into a hotpot. It's wild seeing them at first thinking everything is A-okay before they tasted something horrible and goes "Oh god oh fuck."
It got animated as 'puchisanji' in the official YT channel and it's also fun to see as well (translated to EN using YT closed captions)
Anyway, I can't really say much regarding Inui Toko, so I just gonna drop this clip instead.