Oh, I'm sorry) I might have misunderstood that moment). You're right that "dude" actually can be used for both males and females.
Also I'm not sure if in this conversation with Thane, Quill and Arshem it was a bug that Thane used "them" when talking about my MC, since she is female with female pronouns. But maybe by "them" Thane meant MC and Quill. I'm really not sure if it's a bug. Sorry if I'm bothering you for nothing.