I'm guessing there's a reason there are no questions on SO about how to work with Unreal. Is it because working with Unreal is under NDA?
"How do I get all actors when in cpp? I see where to do it in script."
Probably because we have a Game Development site for those types of questions. unreal is a kind of odd tag, it could have ambiguous meanings. It'd be more likely to find something by searching for UDK, the actual development kit.