Infrastructure for creating a course (Education)

I have enrolled on the different online courses for Teams (and passed them lol) yet I am still not clear on the best way to set up my course text and workbook.

For example:

• a few years ago, when I started using Office365 I created a OneNote notebook and enrolled my students.  
• When I discovered Teams, I created a Team for my class and set up the Class Notebook within the Team. The following year I was able to create a new Team and import the existing ClassNote book from last year's team.
• I have now created a new blank OneNote notebook and added sections for each unit in the course (before I had every unit as separate pages in the Content Library).   This is to organise it better so each unit looks like a separate chapter for each unit.  The plan is to import this when I create a new Team for a new class.  QUESTIONS:
  1. As there is no content library as I started this OneNote notebook from scratch, I am worried that when I import into a Team, the sections I have created will be editable by students.  Is this the case? 
  2. If they are editable, how do I make all these sections non-editable? 
  3. If they have to be in the Content Library, I cannot see how sections can be added to a Content Library.
  4. I would prefer sections and then distribute sections/pages as and when.

5. Is there a better way of approaching this?

6. Am I right in understanding that you do not need SharePoint if using Teams or is it better to have SharePoint and link everything from there?

Thank you.