This may help: http://docs.moodle.org/19/en/Question_permissions_explained_with_diagrams (I hope).
Teacher's cannot edit questions in system level catagory
Thanks Tim. I had reviewed that but hadn't yet made the connection that the user had to be assigned at the system level rather than the course level (despite it being clearly described as such ). Once I understood that and added that user to the system level and assigned them as the teacher the course level, it's working perfectly.
Thanks for the help everyone!