I've seen "shell off" in fics often enough to take it as read, if not as heard, as Carapace's detransformation key phrase. As for Rena Rouge, her wording doesn't entirely fit the pattern (yes, I have seen Timetagger, and Bunnyx's phrases fit thematically as well as excellently), but I still think "let's pounce/let's rest" suits an energetic fox quite well. *shrugs* YMMV.

Miraculer? Ah shoot! I was thinking it was a play on spectacular. *fixes* Cheers.

Re Mayura: I wondered about that! It's not as though anyone has used the word sentimonster, or even seen a sentimonster save the first instance of one, in aired episodes between Mayura's first appearance and Miraculer, and yet Ladybug knows exactly what's going on. You're right: Something must be out of order airing-wise.