There are two different aspects of Needs - the needs of the system itself, and the needs of the individuals within the system.
Why does this system exist? Wherever you choose to draw the boundaries of the system in question (team, department, value stream, etc), you should answer this question through the eyes of its owners or sponsors. What is this system a part of? What is it’s purpose in the bigger system? In other words, how does it support the greater need of the system of which it is a part?
At an individual level, what needs does each person hope to have met through being a part of this system?
You can not give needs to individuals, you can only align their strategies for meeting them to each of the other people in the system, and to the needs that have been identified at the system level.
For some further examples of Needs, see the Catalogue.