@syhue2 , Yes you can do all the edits you want after the course is published, that includes adding or removing sections or videos, updating videos, changing course description, etc.
I would not recommend publishing a course before it is completely finished if that's what you are asking.
Is this still the case? Can I replace my course videos with a better version of the videos? I wanted to add more content to my chapters and improve the quality of the videos as well. Would appreciate a response on this one.