The JFBContent plugin will help you to put it on every article. However, for your purposes, it sounds like you'd want to use the JFBCLike and JFBCComment modules. You can place these on any pages you want them to display on using the module manager. For a lot of flexibility, we'd highly recommend the "Advanced Module Manager". This extensions is great for very specifically saying that "Module A is displayed only to registered users on pages x,y, and z if they registered after 2010", for example.
www.nonumber.nl/extensions/advancedmodulemanager
If you have any questions, let us know. Unfortunately, there's not a super easy way to do what you're thinking. We're constrained somewhat by Joomla's module system, but the Advanced Module Manager is a great way to overcome these limitations.
Good luck!
Question in LIKE and Comment
