Who is she, again? XD I think it's safe to say Kat knows Sophie. I don't know how much of the voice testing is canon? I'm fine either way, just let me know.

Kat probably is aware of Katya (since she's a Royal) but probably doesn't know her? Monty she probably doesn't know. I'm pretty sure they took horseback riding lessons from Master Kumar. Cooper she should probably know since they work in similar fields. He's also a sculpture, though a lot of people don't know that. That's all I got right now.