Ignore, Inform, Involve, Decide, Delegate

I must admit to being slightly unclear what exactly the role of Wardens, Standing Committee, PCC, church council, diaconate, eldership, church meeting, AGM etc. should be.

When should you:

(1) Ignore them!

(2) Inform them

(3) Involve them

(4) Decide with them

(5) Delegate a decision to them

What exactly are their rights, powers and responsibilities?

Trinity & Eldership

Do you think that the doctrine of the Trinity implies that each local church should ideally have 3 Elders?

And do you think the nature of the Father and the relations of the persons suggests that there should be some kind of "lead" Elder?