Hi, dear.
I have just read your project carefully and got some certain ideas.
I'm an back & front end developer with my mobile developing companies.
During back end development(mainly) I developed many backend Admin sites using CODEIGNITER.
******
Codeigniter is one of the PHP framework implementing the MVC theory.
So, your requirement 2 can be solved through CSS&JS.
And solution of other 5 problems may be focus on the CONTROLLER function.
I can ensure this.
******
So if you offer the opportunity , I can complete your project perfectly in time with HIGH quality..
I wish to discuss more details with chat.
regards.