Assignments in categories

A couple of our test consist of student writing a report of creating a project. To grade these projects and reportm, they have to upload them in an assignment. In the assignment list we seperate each course into its own category. However, most student simply click the top category and upload, a lot of the time, the worng product with the wrong assignment.

Is there a way were we can limit the amount of assignments we see in the assignment tab (within course materials we already work with availability data)?

Is there also a way we can limit the amount of times an assignment can ben turned in, within a category. For example, they can choose between four deadlines for one course, but they cannot chose all four, only two out of the four. If they turn it for the second time, how can we prevent they will turn in a third time?

Thank you in advance.