Hello,
Thanks very much for your response. I hadn't thought about Commons and am not terribly familiar with it, so I'll look into that.
I also don't think I explained myself very well in the original post - I create and design the courses in Canvas in what we call template course shells, which I then import using course migration into instructors' live shells with students, so I'm importing all of the course content at once. Afterwards, though, sometimes there are errors, changes, etc. that need to be made to an assignment or a page, and I have to manually open sometimes 15 live courses and update each page individually. I have admin access to all of the courses but I'm not technically a user in them.
Now that I've looked at Commons, it does look like I will be able to share an entire course and apply updates which is useful, but do I need to be a user in the courses in order to do that? (I couldn't find that on the Canvas resources pages you linked) I try to avoid that since I over see 200+ individual Canvas course shells.