Wordpress plugin development

I have a script entitled "Easy Coach Pro" that I want to have created as a WP plugin instead. The purpose for this plugin is for coaches to have a password protected area where they can communicate with their clients on a one-to-one basis. Communication will include an ongoing thread of questions and answers, similar to what might occur in a support help desk. Example: Customer logs in and asks the coach a question. Coach logs in and answers the question. Customer logs in to continue the conversation. Coach logs in and types a response. The ongoing conversation is kept intact in the private, one-on-one area. Coach will interact with numerous clients, each in a private area as previously described. NOTE: I will use "coach" and "admin" interchangeably below. I will use "client" and "member" interchangeably as well. I will need both an admin and member area created. Features... PRIVATE MESSAGE AREA FOR EVERY COACHING CLIENT. Each member is assigned their own unique private message board for the coach to interact with them one-on-one. Plugin should be able to generate an unlimited number of private message areas. Each coaching clients should receive a username and password to access their unique message area for security. No one else is able to view the communication between client and coach. Administrator/coach will have access to all clients usernames and passwords. ONE-CLICK ENABLE/DISABLE FEATURES. If a coaching client requests a refund or discontinues using service, coach should be able to disable their access to the personal message area with one click. Likewise, they should be able to enable an inactive personal message area with one click. AUTOMATIC OR MANUAL SIGNUPS FOR NEW CLIENTS. Coach should be able to direct clients to a "signup" page after they have paid for coaching privileges where they will choose their own unique username and password for access. The plugin should automatically check for existing usernames and prevents duplicate entries. Coach should also have the ability to manually add new clients. ABILITY TO UPLOAD FILES AND CONDUCT LIVE CHATS. Both coach and client should have the ability to upload files of all sizes and formats for sharing, again utilizing the password protected secure area. (Files and chat are only viewable between coach and the individual client) Additionally, the plugin should have the ability to conduct a live chat with individual clients (I.E. Similar to instant messaging). EMAIL NOTIFICATIONS WHENEVER A NEW POST IS MADE. Coach/admin should receive an email notification anytime a coaching client posts a message to the personal area. Likewise, clients should receive an email notification anytime the coach posts a message to the personal board. This works for both original posts and replies to existing posts. CUSTOMIZATION OF ALL YOUR COMMUNICATIONS. Coach/admin should have have the ability to customize all automated messages including: the "welcome" email clients receive upon signing up, the password retrieval email, the admin has posted a message email, the client has posted a message email, etc. SAVE ALL MESSAGES FOR FUTURE REFERENCE. All correspondence within the message center should be archived until admin/coach deletes it from the system. This allows coach/client to refer back to previous posts at any time you need. AUTOMATED PASSWORD RETRIEVAL FUNCTION . Should a coaching clients forget or misplace their username and / or password, there needs to be an automated password retrieval function where they may generate an email message which will send them their login details. * Only 100% original code should be used. * I will own all rights to the plugin and you may not use it, in whole or in a part, with any other project. * Bid to include 90 days of ongoing support to fix any bugs, troubleshoot probe. * I will need an installation guide and user guide created with screenshots. * I will sell this plugin commercially.