JFBConnect doesn't store a user's profile data itself. We do work with multiple 3rd party extensions, like JomSocial, EasySocial, Community Builder, Kunena and even the Joomla User - Profile plugin to store a user's profile data into those extensions. To set that up, enable the Social Profile plugin for the extension you want to import data into and then configure how the data should import in the "Profiles" admin area of JFBConnect.
As for the registration options, it's up to you how to display them. Once the user clicks a social login button (Facebook, Google, Twitter, etc), they are choosing to login with the social network. The profile data can be auto-imported or you can send them through the 'mini-registration' where they can see the data and add new information for their profile. Otherwise, they can choose to register the normal 'joomla' way and create their username, email, password, etc.
I hope that helps explain, but if you have any questions, just let me know.
Thanks,
Alex