You are hitting on one of the difficult things to balance. One of your roles is to act as an information filter in both directions - but this is more often done too conservatively rather than too liberally.
My advice would be:
- if the information is providing context on current work, or information that will affect the teams tasks/deadlines/etc. share it as soon as you can
- if the information is of the "might happen in the future" variety don't share it until it's concrete. Vague concerns that aren't actionable don't help anyone, and will stress some people out.
- it's trickier with things that are less clear cut (e.g. this other team/division is having a real problem but nobody knows what to do about it yet.). In this case I would lean toward sharing the positive things and holding on the negative ones while they are still uncertain.
- it's also very dependent on the person. Some people want to know a lot more details to be comfortable than others. One size fits all probably won't work that well. Does the team feel comfortable about approaching you for more detail?
Finally a question - how are you "managing up" for this team? To use your example, if your manager tells you about a customer meeting with a deliverable and date that will involve your team, how are you making sure the team has meaningful input on scoping that deliverable?