amember integration in an existing web cloud platform

Hi! I need to integrate an existing web cloud platform with a membership software [login to view URL] I want that when a new user go to a landing page (not the same as the cloud platform) He/She can choose from a number of subscription option (Free trial for a limited time, Standard, Premium and so on... see attached file). When a new user has choosed the right option, He/she complete a registratio form and than He/She will receive a valid account to login to the platform (different from the landing page on wich He/She has registered) and from this moment He/She can use the platform accordingly whit what has subscribed. Obviuosly when the trial or full subscription will be expired the user can't access the platform in anyway until a new payment (renewal). In addition, I'll must free of any change to the number and kind of subscription option on the landing page at any time, One of the most important requirement is that there will be a full integration between the membership software and the web cloud platform that has its own user database. In other words when a user has completed its registration form, He/She will receive a valid account to access the platform - based on wich has purchased and for the time that has subscribed ( a week, a month, an year and so on...) - in a totally automatic way without any human intervention.