JFBConnect can automatically (or manually) publish Joomla articles to LinkedIn Company Pages as long as you're a member of the LinkedIn Marketing Developer Program. We do not currently support publishing to Instagram. However, we can push to Facebook Groups and Pages and Twitter Streams.
In bringing back content from the social networks, we do not create Joomla articles. The posts are displayed in our SCSocialStream module (which you can theme to fit your page). You can see this module if you scroll to the bottom of our page. Likewise, we currently only support the same channels: LinkedIn Company Pages, Facebook Pages/Groups and Twitter Streams.