Repository Separation of Responsibility

[dpgraham4401]

Description

Some quick chores and just refactoring of the model manager interfaces.

Issue ticket number and link

Checklist

• [x] I have added tests that prove my fix is effective or that my feature works
• [x] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings