1) Copy Geometry is used to pass geometry references from one model to another. Example:
You are working on wheel design. You will need to know the rotor geometry to which you mount. You create a CopyGeom feature of the rotor mounting surfaces in your wheel model.
2) Shrinkwrap creates a part that represents the bounding envelope of the assembly or part. It will remove internal details.
Example: You designed an engine, but the car body design guys need to know how big to make the engine bay. You make a shrinkwrap part of the engine and give it to them. It will not contain your cylinder bore or crankshaft geometry,...
3) Merge/inheritance is similar to CopyGeom, except you get the whole model and it can be associative or not depending upon what you select.
Example: You make a contact lens that swells when it hydrates. You need a model of the unhydrated and hydrated lens. You create the unhydrated contact lens and then create the hydrated model as an Inheritance feature. Apply your expansion factor and voila, you have 2 related models.
4-6) I don't know, as I don't use them.
