All would be down with small talk.
Emma (Ava) : Her and Ava are already sort of friends, so she’d feel comfortable chatting with her about at least surface level things. (Would hesitate on asking her about herself though, knowing Ava tends to be a bit touchy.) If she picked up on Ava’s love of cars you can bet she’d ask about that. (And probably fail to comprehend any technical terms she might bring up. She’d enjoy seeing her talk about something she enjoys other than work, though.)
Cassandra (Nat): Lover of stargazing, myths, tea, reading, nature, and animals. I’m sure she and N wouldn’t run out of things to talk about anytime soon. She’d also ask Nat about herself, but would try not to pry.
Hayden (Morgan): Snark and sarcasm, with some genuineness on the side. Her and M flirt all the dang time, so without that she’d lean more towards playfully poking at M, and making jokes.