Hi,
Just came accross your post. I work with clients with similar requirements and below is the set-up we use.
WishList Member – to control access to courses (are all paid subscription) and roll-out access according to a pre-defined schedule.
We uae a product called Quizbuilder (Tanida Software) to create/post the quizzes. You can control all aspects of the quiz functionality and reporting.
What theme are you using? I’m curious as we have been using Flexx and Socrates and are looking to make a change.
Hope this is helpful – I realize that it has been some time since you posted this.