Good afternoon Nick,
This is fairly simplistic, and doesn't really need a plugin.
The main problem is you can't hide comments that are directed from Facebook, but if you're referring to WordPress comments, that's an easy fix.
As for communication, they will provide you an email address when commenting, so this gives you an opening for direct contact.
As for uploading testimonials your have received by email, I'm assuming you mean directly onto your website, and not within facebook, correct?
Please message so we can discuss this further,
Daniel Larson