Nah no rules with naming. And ojih.....I’d say generally no. They might know enough to distinguish high rank or something (they would probably know how to spot a Sol, Taja, and Eija. If they were the sort to spend time learning the marks they might know Ridahne’s treason mark. The mark itself is nonspecific, so they wouldn’t know she killed the equivalent of a princess, but they would know she has committed some form of high treason if they knew the mark at all. Those that deal with the Azurei more directly (royalty, merchants, or people that often hired Eija guards) would be more likely to know tidbits about the Ojih. They do know it’s significance and they know it is extremely rude to touch an Azurei’s face without permission.

Also yeah, Ridahne definitely knows, though she’s more stunned by the fact that Darin would keep her, as she assumed above all else she wouldn’t.