Very difficult to control who is the teacher named on the 'you need an enrolment key from' page.

The manual enrolment plugin pulls the name of whoever happens to be first in the list of users who have moodle:course/update capability and displays that as the contact for the enrolment key. That's a bit unsophisticated. It's very difficult to manipulate who that name will be and getting the wrong name here can be a major annoyance to the victim.

My suggestion would either allow the contact to be specified in the course settings or to dump it altogether.