Creating Functionality on Website - Magento

Hello, I need the following work doing. The website has been fully designed (so no or very little design work is required), and built with JQuery and JQuery Mobile, its also built with HTML5 and CSS3. The web site main functionality: - Display products only available for this web site. - There will be no need for a "cart" as it is a single buy item, but the user set a quantity of the item (ie Cannot purchase 2 different items at the same time, but can order 2 of the same item). - Magento Login and/or Registration. - Customer data retrieval and submission. - Payment Processing via SagePay API - Order submission to Magento (Upon completion, and payment successful) More in-depth details: 1: JQuery needs to retrieve a JSON file from a web server, parse the objects and place into the website upon loading using AJAX. 2: A PHP Script that will retrieve "specified" products from a Magento store and add the objects to the above JSON file. 3: The web site needs to be able to login in the Magento store (Using the Magento API), to retrieve customer information. 4: If the user is not registered, then the ability register is required, and the details are saved and submitted to Magento. 5: Payment processing using SagePay API and order submission to Magento via AJAX. - Forms needs to be validated. - AJAX loaders should show when the website is retrieving / sending data. - Images like Promotional Banners and Product Images will also be stored on the web server so we can change them without needing to change this website. We are not just simply looking for a 2nd store website, the long term goal is for this to run as a mobile application, hence why we need it programmed with JQuery and AJAX. All PHP files will be located on the web server, and this web site will communicate back and forth using AJAX. This website should be able to run on your system locally and function correctly, all that would be required is an internet connection, and our web server to be online! The main JSON file will contain the configurations etc (Name of website, telephone numbers, promotional banners, products, php file locations). You can alter the current HTML files to have them in a single file if you wish. This also needs to run fast and should be optimised, so removal of any HTTP requests that not required should be removed. Also removal of any CSS / JS files that is not needed should also be removed. Maybe this is possible: Is it possible to bypass Magento? Such as just go into the database and do what we are requesting? --- The next phase after your done, will be to compile the website into a mobile application using PhoneGap, but this will not be done by you! So everything needs to be fast, optimised and functioning correctly. Regards.