Our briefings are electronic. There is information from various departments (safety, service etc) usually regarding any recent changes. The managers can also talk about anything they feel important to pass on. My last briefing had a slide reminding us about the lounge changes in Singapore in case anyone asked.
UM's are definitely mentioned, as are the number of wheelchair passengers. Individual passengers are not usually mentioned. A large group, perhaps. The managers may be aware of something in regards to a specific passenger on the flight, especially when there has been a recent interaction with customer care. They then usually pass that on to the specific crew later that will be taking care of them as the briefing (which is only 10 minutes) is best spent on covering topics that impact all the crew. But the managers will use their discretion and if they feel it is important to share it, then of course they can.