Modify User Manager for existing Joomla website

The standard User Manager registration process needs to be modified as follows so that registration is permission-based: 1. add Company name, Position, Telephone and Verify e-mail fields to the required fields (the final order of the fields should be Name, Company name, Position, Telephone, E-mail, Verify e-mail, Website (optional), Username, Password, Verify Password); 2. on registration an automatic email is sent to the user stating that they will be notified by email once their account has been activated; 3. once the account has been manually activated (by me once the user has been approved) an automatic email is sent to the user advising them that their account has been activated. I also need a couple of minor cosmetic changes to the site: 1. reduce the size of the company logo at the top of each page; 2. replace the Joomla icon with the company icon in browser tabs.