. Also, the main evidence Zeb/Dusty used throughout were the family records that "proved" Stheno was a commoner. No, they "proved" Stheno started a life of adventure. Its semantics, yes, but apparently this entire matter started with semantics.
The part of the family history that's most important is what's missing. Theirs no affirmation of her becoming a noble. According to the family history she was born a commoner and she died a commoner.