How much they know is totally up to you! Maybe an info broker sold just enough data to someone to paint a target on him a few days in?

Not sure if Kanda would ask - he's already on friendly...ish? terms with Jennifer (also a Derrish not!it!heir,so he's probably going to want to make sure she's safe.

But I can totally see him calling Koon out on it and asking why he isn't running home yet. Because let's face it, Kanda's an asshole.