So the way things tend to operate is staff will not really tell you explicitly what you can or can not do IC and what the effects might be. I believe it has been mentioned in that linked thread that there is a consistent policy, so things aren't arbitrary, but that players are not necessarily privy to it.
Which is to say, as mentioned in that thread you can engage in certain crimes topside without xhelping first, but that doesn't mean you're told you can get away with X, Y and Z IC.
As far as what you can mechanically do, NPCs and PCs all work the same when it comes to command verbs, but I would be read over help farming and help npcs to avoid getting into OOC issues. IC issues are up to your character to resolve.