Hi, welcome to the forum!
The idea is that we enable a school district's IT people to create student and teacher accounts and put students in classes. Multiple teachers per class is a great idea that I hadn't thought of, but yes, we should allow that.
This part isn't settled yet, but I think we should have an explicit "submit" button in the save dialog that puts a time-stamped copy of the project as it exists at that moment into a sub-folder of the teacher's (or teachers') account. The student(s) can then keep working on the project, and teachers can decide whether to look at the latest submission, or the last submission before the deadline, or whatever.