They're not difficult to recognize. Eleanor is the only girl who can enter this place other than monsters... and her hair stands out. While Rosenkreuz... Rosenkreuz is definitely noticeable. He wears his blue dragon armor constantly, and there is nobody else who can fix you in place with just a stare so effectively.

...most methods of address are merely habitual. I am not so familiar with Eleanor as to use that version of her name while interacting with her. But since you used it, it suffices.