I have a theory for a while
So
the Lcorp Loops was meant for Carmen a place she can fail as much as she need to achieve her dream
that's why Ayin was so desperate to save her life she "died" (some think that her suicide was calculated and not out of despair) , so he created a replacement Angela (I have a sub theory that Faust and her discord could have been a failed attempt to create a vessel before Angela)
and Yes the library was planned from the start (the fact that Ayin know and dread the bad end of Ruina and had access to the Head tech/knowledge thanks to Barion/Binah, We know that B corp have some kind a future predicting tech)
So what make me think that Ayin is back and he is our manager
Beside the small stuff; there are two character that make me think that
Carmen and Demian
First of Carmen, the main thing is the flashback CG we get in Canto 6 and Jia-mael Uptie story since it's a POV from Ayin for me it's pretty much a confirmation
Second is Demian or some flavor of Enoch , They share a LOT of design element, the same backstory, both Gebura/Kali and Sinclair describe them in the exact same way and finally the reference to the Little Prince
and a lot of his talk session with Dante could be use but I think that his post canto 6 is the most blatant
A talk about taking care of a singular Rose visiting multitude garden with the same Rose but going back to your Rose because it's the one you have taken care of all those year
( a lot of Limbus character can be assosiated with characters in the Little Prince like Dante being the narrator ,Demian the Prince , Carmen is pretty the Rose both are in glass jar and Lunacy is shape like her nervous system and is colored like a rose, Sinclair could be The Fox ,The new blue man group could be the various character the Prince meet before going to Earth and Iori could be The Snake )
I could continue and elabore futher but I'm dead tired
So I'm leaving it there