What about characters from other cultures?Quick reminder: At this point, no characters are really close friends with any other characters yet, so, supposedly, no characters should be calling others by they're first names.
...Save for Yusuke and Zasha since they were friends for a while before.
Zidane is, for example, Arabian if I remember correctly, and my own triplets are actually Welsh. As I would recall they introduced themselves with their first names rather than their last names as would usually be done. Of course, I don't mind editing a bit for consistency; I'm just wondering how characters who weren't raised with those sensibilities would be expected to act.