Stephen,
Sorry for all the troubles you seem to be having. It initally sounded like a bad installation of JFBConnect, which was mostly corrected through uninstalling it.
If you're not seeing the Login With Facebook button, it's likely because the JFBCSystem plugin isn't enabled. Please make sure the Authentication, User, and System plugins for JFBConnect are enabled. Those are all required for normal operation.
If that doesn't help, just let us know!
Thanks,
Alex