WordPress multisite app register account with eBay

Hi there, Looking for someone very specialized in working with eBay API's and WordPress MU. What I need is a secure way to register a new website (sub domain in WordPress) with eBay logins instead of regular email, name, pass. So the register page should have a button, when you click that you get redirected to eBay to login there you have to accept to use eBay with my app than behind the scenes you have to get: name, email, PayPal, store name, store country, pages, categories. The register will create automatically a strong password and email to me and user the details. I use a WordPress plugin to work with eBay - you have to use that too. After register, each user must have WooCommerce + few more plugins active in their account after register. All this must be very secure and work with SSL. Thanks!