Develop custom Drupal functionality

Hello, I am looking to hire a developer to build "activity workflow system" functionality into a clean Drupal install. Introduction: Certain ‘activities’ on the website require approval by other users. For example, the website contains ‘activity’ nodes, which employees can ‘mark as completed’. When the activity has been ‘marked as completed’ by a user, it triggers a workflow process where the users manager must ‘approve’ or ‘deny’ the request via a simple 'managers dashboard'. The request will also be visible to the user via a simple 'users dashboard' Once the request has been approved, the ‘activity’ node will appear in a ‘My completed activities’ section on the website No design or theming is required for this project, just the basic functionality outlined below User: - Marks ‘activity node’ as complete via front-end interface System: - Notifies users manager Manager: - Views notification in a simple manager dashboard Manager: - Approves/denies/requests more information on request System: - Sends notification to User User: - Receives notification in a simple user dashboard - User can respond to notification, triggering a manager notification System: - Updates activity in database so the front-end can display users ‘completed activity’ via Views Additional details: - The system will be developed from a clean base-install of Drupal 7.38 - The developed system should utilise JSON/AJAX for communication between client and server, so that the front-end of the website can use Javascript libraries (Handlebars,underscore,jQuery) i.e. - The ‘request for approval’ should be sent in JSON via AJAX when the user interacts with the website - The managers dashboard should get data in JSON format - The managers ‘approval’ functionality should send in JSON format via AJAX - No theming is required, just the functionality - Basic documentation for how the system works - Well commented code (EN) - Developers choice of third-party Drupal modules (if required) - The functionality should not be restricted to one single content-type, i.e. different kinds of 'activities' can be integrated into the approval workflow