If you go to People, then click on the option to +People, you can designate roles to another teacher and set which section to add them too. Say you have a 2nd hour class. You can designate another teacher as Co-teacher, then use the checkbox below that option to only allow them to interact with users in their section. I am not sure if that will limit their ability to see other sections, but they will not be able to interact with (including grading) those other sections. Here is some info on Canvas Roles. A Co-Teacher will have the ability to edit content. If you ware wanting to prevent that, you may need to talk with an account admin for your district to create a role that gives/limits the permissions you desire.
If you have other teachers as Co-Teachers, this would be the way to go. Your comment mentioned allowing teachers to tailor their version. If you have courses where someone else is teaching (not you), then that would be a separate course, not a section in the course. I'm a bit unclear of what you are wanting to do with that aspect.
I cannot say why it is creating a duplicate module when you change the blueprint. I have less experience with creating a blueprint.