Unfortunately, this does not help in this case. Calibrating a scanner also involves the emulsion properties (which, by the way, also holds for colour slides!). First, there are no targets available (with very few exceptions) for colour negative films. Second, if the film has aged, you would need a target with the same emulsion that has aged the same way, which is not available.
I completely agree!
Yes, there are. They come with film specific profiles, which, in some cases, can be modified by the user to match properties of his film, again by eye, if the material to be scanned has aged and changed its colour properties.
Hermann-Josef