My approach to Rosalind's personality during the MMF scene was similar to the kitchen scene where she's egging on Edwin's dirty talk, only her wiles are directed at two. The vibe's a bit different because the scenario's changed, but I don't think there's anything incongruent there with how she's previously been portrayed.
Still, out of all the characters in the game, I will admit Rosalind's voice is always the most difficult to conjure. Maybe that's owed to the nature of her character, or more likely, because her personality has been pigeonholed by the overtly blunt parrellels with Victoria. Either way, I'm hoping the next couple updates will fill in the gaps and make her more concrete. Like with the one-on-one conversations with Ian, I wanted to reinforce some of the brief glimpses you get earlier in the game when she drops the 'act,' as well as unsubtly bring up the question of her own past.
Anyway, it's food for thought.