Administration of Active Directory does not have to be hard. Too often what should be a simple task is made more difficult than it needs to be.The solution? Hyena from SystemTools Software. With ease-of-use as well as powerful importing and bulk updating capabilities.
Not if you are logged in as an administrator of the server and created the folder. Domain admin is sufficient.
Don't know. Depends on several factors ... disk speed, CPU, RAM, what other applications are runnng at the time of the move ... that varies from server to server and company to company.
Personally, I would perform the move after hours.
No.
=====
Quite honestly the only thing you need to do is change the location of the database files in the database properties within the Exchange System Managers and the rest should be taken care of with the move.