Well - I finally figured it out. All I did above worked fine. I thought by taking those steps, it would auto-populate the courses under where it says "Topic outline" - but I realized I needed to manually add the info for that "Purchase bundle" course, and add info and links for each of the 3 courses, under each of the 3 topics. Once I did that, it appears that was the part I was missing!
So I believe this issue is fixed. Thanks so much!