Shall we add the classes which is out of scope of the use cases, such as a Session Facade for user authentication and authorization or a DAO to manage the users of the system, into the class diagram for part II?
I think that we should create the class diagram and component diagram with all classes, not only the ones used in sequence diagram. Because we should create the class diagram for SuD, not only the use cases.
That could explode the number of classes in the class diagram when assessor are only interested in how you are solving a particular problem.
It is also ok to list in the assumption that classes for user authentication, logging etc.. or anything that is not in the use case are not provided and or
already known to the system developers.