Amazon Seller Sales Web App Needed

I am in need of a web application utilizing PHP/MySQL that helps Amazon marketplace sellers track sales and fees. This application will provide an up to date snapshot of an Amazon marketplace seller's sale and fee history. I have many things I'd like to do with this project such as generating easy to understand graphs and will most likely continue further but to get it started I want the following milestones to be completed to mark the first phase as done: 1. Implement a username/password database with a user management interface for an admin and to have the ability to associate a particular Amazon seller's account and password. Password has to be stored securely. 2. As often as possible, retrieve select information of that particular Amazon seller's order information through Amazon's MWS service and display in a table. 3. If Amazon's API does not provide it, calculate and display total fees for non Fulfillment by Amazon orders that the seller has incurred such as commission and the variable closing fee in an intuitive format. 4. If Amazon's API does not provide it, calculate the various shipping methods (Standard, Expedited, International) that the seller's customers requested and create a summary of these orders along with the total shipping credits for each that the seller received. 5. Integrate Paypal's API to provide the ability upon a customer signing up for this service as a Paypal subscription to automatically create a username requested by the customer and to generate a secure, random password for the user to initially log in with. Upon login, prompt to change the password. Conversely, when a customer cancels the subscription to automatically revoke access. 6. Provide ongoing maintenance and support of this application through it's lifetime. I am attaching a spreadsheet of what I tried to start but I've found this is not scalable and too time consuming for me.