I like where this is going!! and I didn't know Rin was an artist too.
Uh, she was head of the art team for the first two volumes before Kou took over. She just did environment and scenery art, not characters.
Did we ever actually see anything that she drew? For everyone else, seeing their actual creative production is a bit of a moment of truth for their characterization (when we get concrete evidence that Aoba is very good, but still not as good as Kou, etc.).
I’m sure I could be forgetting something, but although if I had thought about her job title and the references to the past for a minute I would have realized that Rin must be artist herself, when I think of the character I only think of her as being an administrator and liaison with the higher-ups at Eagle Jump.
Obviously, a careful re-read of the entire series is in order—I’ll have to notify everyone at work that I’ll be occupied for a while.