"Venus smiles in the way that makes everyone want to punch [her] a little, […] Venus can smile and laugh nervously through anything."  

From the wiki: Venus is timid and shy, masking a deep anger at the world and at Summer Scouts in particular. She doesn't hesitate to argue back when Group South picks on her, but instead of hurling insults the way they do, she just tells them why she thinks they're antagonizing her. 

Venus is a trans girl, so I'm not going to be very picky with who auditions for her, but she should still be portrayed as generally soft-spoken and bright.