I would definitely recommend disabling those plugins, temporarily, to see if the JomSocial registration flow works as expected. If not, see if you can use the JFBConnect registration flow. It definitely looks like it will need some styling work on your site though, so that may not be a great solution.
Finally, we just put up our blog post about the current and upcoming changes in Facebook:
www.sourcecoast.com/blog/facebook-is-cha...-jfbconnect-is-ready
Thanks,
Alex