The written by line is being hidden by the following CSS code:
.parent-category-name span, .category-name span, .create span, .modified span, .published span, .createdby span, .hits span {
display: none;
}The ".createdby span" is what surrounds the name of the author. Your CSS is compressed, combined, and minified, so I can't tell you what specific file is adding that to your CSS... it's not JFBConnect though.
As for the social sharing buttons, check the following:
* The JFBCContent (content) plugin is enabled
* The social buttons are enabled in the JFBConnect -> Social configuration area.
I hope that helps,
Alex