School management plugin development idea

Hello Everyone,
I have been commissioned to develop a school application, to keep records of student, students can login to check their result, teachers can enter students grade, school admin can create a new school calender and manage students and staff records.
What I want from the commyunity is suggestions and idea that will make this project a success.
What I want are

• I want to know how I can create a custom user (students and teachers) with their role and privileges.
• Assign teacher to a subject or course
• assign students to a particular teacher as mentor or guide

I think solution to those questions any suggestions and idea is welcome or better still their is a ready made solution that meet all these requirement.

Thanks in advance