Dear Sir or Madam:
I can do a Sheet as DB, and the GUI could be in Google Forms and email, triggered by email sent by teacher using macro code.
I am a teacher+programmer+LMS specialized, I can understand your need, of course your budget just last 40 hours. I can not deliver a perfect LMS with Google Sheet. To keep security, just administrator could use Sheet, user must fill Forms and Read in Google Sites or Data Studio or Mail all data they need. I could make FOrms to get Request of Reports.
Teacher can fill student progress in the SHeet, but other users must use it with care to be the system reliable.
I am a programmer with extensive and wide experience in software systems, integrations and the requirements you posted.
I am bidding in your project with foundations that make it get ASAP ready. Please message me to define meeting´s time to fix details and I will show you video sample of my experience.
Thank you,
Background
Full services: programming, PM, technical translation/writing.
Software architecture and engineering.
Personalized service, full back-end and. front-end programming.
Remote Work
-Online distance working.
-Online collaboration: Dashboard for auditing advance.
-Daily communication automatized workflow.
-Extreme programming, Agile methods.
-It Includes state of the art analysis AND design.