This is a dilution of the meaning of "dark pattern". darkpatterns.org which coined the term (and Wikipedia cites) says,
"When you use websites and apps, you don’t read every word on every page - you skim read and make assumptions. If a company wants to trick you into doing something, they can take advantage of this by making a page look like it is saying one thing when it is in fact saying another."
I don't see any of that in your observations. Moreover, what you attribute to some nefarious purpose is better explained by effective curriculum design. I haven't used edX lately but I worked at Coursera and I can tell you that the people who make that product have a passion to support learning in the world.
* Removing access to course materials: it's a course, not a content library. When you can access it anytime, you're less likely to do the work of learning. You also won't be part of a learning cohort, which is a valuable learning activity.
* Encouraging you to sign up for courses: this is a problem? Wouldn't someone who wants you to learn encourage you to sign up for courses? "Course began ($TODAY - 5)" that would be deceptive. Are you claiming that edX or Coursera does this?
* Breaking courses into chunks and quizzes. How the heck is this deceptive? This design decision is backed by learning science. Listening while doing dishes does not get you the best learning outcomes; it's a university-level course not a podcast.
* "Unsettling UI" "opportunity to pounce" I really don't know what to make of this one.