About Oriel and Noir, I know nothing mind you, but I feel like there's a chance that they were always part of Mercredi's downfall. As in they aren't real. If I recall correctly they only ever appear in isolation alongside Mercredi and don't have any interaction with the rest of the cast. Plus it's a bit suspicious that alongside this one of them is a slightly snide, but in an attempt at humour, sheep and one of them is an entirely animalistic wolf. It's like they're the two sides of Mercredi.
If you want to reach further Pascal says Mercredi's jokes aren't funny, and there's definitely not much positive reception from her in response to Oriel's mocking tone.
(also Oriel has golden eyes, like Mercredi once had in her flashbacks)