I completely thought Gwen would be a major bitch to any of my fosters, especially a female.
She will get snarky with Bena sometimes, since Bena is much more playful and bigger. Bena isn't much on toys, so there's rarely any issues over wanting something Gwen has. They both love Loki, though and will squabble over who gets to play with him. I've also noticed Gwen is more vocal around Bena.
But all in all, Gwen is top dog. Sometimes Bena will lord her height over Gwen but Gwen quickly lets her know who's staying. They will play rough to a point where I feel like they need to stop. But they've never gotten in a fight. And I'm shocked. Reading Chaz made me kind of terrified to have two females in the same house. It can work! Lol