Can you tell me what "fb messages" are appearing before the form? There's different notifications along the process, and want to make sure I'm helping you remove the proper ones.
For adding the Login With Facebook button, you'll need to modify the module's template that you want to add it too. Then, simply insert {JFBCLogin} wherever you want the button to appear. There are a lot of other options available for size of the button and such, but that's the simplest form. For all the options, see:
www.sourcecoast.com/jfbconnect/docs/conf...ocial-content-plugin
For the Like button, it's a similar situation of adding the {JFBCLike} tag to the Virtuemart flypage. You could also use the JFBCLike module if there is a module position that would work for you.
The Google+, Twitter, and LinkedIn share buttons can be configured to automatically show up in Joomla articles from the Social section of JFBConnect's configuration. Alternatively, you can use the {SCGooglePlusOne}, {SCTwitterShare}, etc tags (also available on that page above).
On the Login form, we have the integration option to add that button automatically. Our auto-option will only add it after the form as we can't modify the form directly through a plugin. If you need to move it, you should disable our auto-integration, edit the login form directly and add the {JFBCLogin} tag. If you need help doing that, let us know.
Finally, for performance, we do a ton of testing and optimization for performance. Much of Facebook's javascript is configured to fire after the page fully loads, which means it adds more time to the end of that process. If you have a lot of other Javascript on the page, then adding FB may slow things down more. Our site, or even the Joomla Extension Directory (which uses JFBConnect) is a good guide though.. if it's a lot slower than that, it's likely either other extensions or conflicting extensions on your site. I'd open a Javascript error console in your browser to see if there are any messages in there.
Hope that helps answer your questions, but if you need anything else, let us know!
Alex