should this be word instead of name?
 There always were. And Mrsha had to come up with a new name for ‘bee’ in honor of Apista

Her running style uses faerie magic and I get the sense that faerie magic might not run on mana

Teriarch did imply that a regular intake of mana into the system can increase your mana pool or at least your tolerance for mana.
But even Ryoka herself seems to have forgotten about that, which I find surprising considering that her new running style probably takes up a good amount of mana.

Who?

Erin doesn’t know goblin speech. She can kind of understand their meaning after watching for so long, but she doesn’t even know as much as Pisces seems to.

Beyond that, while goblin relies significantly on body movements and nuance, there is still some noise involved. Mrsha can howl, but hasn’t been shown to really make even many basic, non-word sounds besides howling. It’s possible she could grunt and growl enough to do a passable bit of goblin, but also entirely possible that she couldn’t make enough different sounds to make it worthwhile.

Developing her own form of sign language would allow her the full capacity of “speech” compared to trying to adapt something else that might only partially work.

To be fair, even Lyonette didn’t initially think there would be that much danger at this time. Yes, she had no safety net of snow to jump into, but she didn’t think the hive would actually be active yet.

“opined for deserts served cold” – I think you probably meant “desserts”? Anyway, what a great chapter, such a joy to reread!