The new "Captain" and "First Mate" appear human, right?

Is there anything that could be learned by listening in on their conversations? Like if Robin used her powers to grow copies of her ears in the rooms they're inside?


Also, worth asking: I assume 'Historian' is not a vital job (although Robin is gonna refuse to do anything but that anyway). Would her books be considered 'frivolous items' and what would happen to them as a result?