About the SB dossiers. I agree that many of them felt like they were made to be humorous. Some of them contain irrelevant intel. I think that may be the intention - in-game intention, even. I don't fully trust the written intel - agents make mistakes, or they just lie, they could've been re-recruited. Only video records are convincing enough, but they're few.
I found TIM's dossier to be particularly uninformative. They managed to breach the security enough to tell how many cigarettes he smokes per day, but not what he's planning? It doesn't tell us anything expect that he smokes a lot, drinks a lot, has a lot of trysts, and sends a lot of messages across the galaxy. It's nothing I couldn't have figured out on my own. I was very disappointed...and I believe the Shadow Broker was, too.
Apparently TIM's security is good enough that only the irrelevant and superficial intel gets away. Maybe TIM appointed one of his assistants to be the double-agent for the Shadow Broker, and the agent feeds SB only unimportant intel, something that sounds believable enough.
And concerning the crew's dossiers, I bet SB didn't know about EDI, and doubtless she handles all the firewalls regarding the crew's extranet activity. Maybe EDI filters information, making sure nothing crucial gets away.