Ummmm I don't think we ever spoke about Devin and Dani. If he knew she was alone in all this he might try to pull her into his remaining social circle.
Ryan doesn't really talk to anyone unless he has to, though I'm sure if he knew Matt or Sonny were 'keeping an eye on him', he'd probably comment on how they have bigger things to worry about than him. He wouldn't be happy if either one of them were hovering about, or were keeping constant tabs on him. The man just needs a good night's sleep, haha.
Audrey was just as happy to find Matt, obviously! And I imagined he'd be protective - I would have been concerned if he wasn't, though she still does like to be independent. And far as I know, Matt does not know about her history with Eli. She may have mentioned that she knew him when he got arrested, but wouldn't have gone into detail on how well.
Yeah, Christian just doesn't want people to think he's unstable, or unable to protect people because they think he's about to have a meltdown. This is why he keeps the fact that he has been taking medicine to help him out a secret. He hasn't had a major attack in a few months, but I imagine he's running low on pills... He'll definitely need Sonny's help to figure out how else he can keep calm under duress.