wath is the difference. all the same?
No. And this isn't the place to give a rundown of what works and what doesn't in education for the last decade. Given our exchange to date, I really must suggest a finished application directed at teachers, like Blackboard.
Bringing a Wordpress or Drupal install to fruition as a working, strategic, application is an undertaking I strongly urge you to never try. A coherent, working project is nothing like what you apparently think it is based upon your sketch.
There are any number of tried, tested, best practices for educators. You can rest assured posting in a forum and expecting to get your homework done by others is not among them.
Read. Learn. There's a good teacher.