It'll be fun to see how they interact in costume. I imagine they'll get along well! Cass and her both know how to fight, so it'd be interesting to have their first meeting be something of a fight and then a moment of understanding that each of them is trying to help?
Perhaps she might know of her? Not sure. Babs was only slightly involved with the Wayne. Went to a couple of parties. If Dick mentioned her, that's likely up to Brett to say yay or nay oh. But if she's aware of Cass, she might have come to see her. Possibly help teach self-defense once or twice as well?