Agreed. Especially if the whole "she's dead" thing from Oka has been a lie this whole time and Kumoko is in fact Wakaba Hiiro, who Fei bullied in Japan. And Oka's trustworthiness is at an all time zero now that we know the elves have been hiding the fact that they have mecha and high technology. Oka knew exactly where the demon guy was too, she didn't say shit to Shun and Katia. If she didn't want Fei to find Wakaba so she could finally apologize due to the danger the demons present, Oka could have lied. Probably lied.
The girl in white and Wakaba's cold flat personality with a tendency to avoid conflict matches. Internally a spaz and crazy, externally distant and cold. And we've never seen the girl in white's internal thoughts.
edit:
Side note I realized while writing this, I like that Fei has actually had one of the better character development arcs so far. She went from selfish and arrogant in Japan, to bitter and lazy as a pet dragon, hints of responsible when she first took levels in taboo to save her friends and again when she made a pact with Shun, back to haughty and energetic once she acquired a human form, to finally responsible and big picture strategy in this episode.