You'll simply need to disable JomSocial's Facebook features. However, right now, we don't import any user connections that have been already made in JomSocial. Because of this, user's log in through JFBConnect may create new users on your site if they don't link them to an already existing Joomla account.
We plan to implement an 'importer' into JFBConnect 3.1 for both Community Builder and JomSocial.
What to disable/uninstall if JomSocial FB Connect is already active?
