@Guy-and-Cassie0 My spidey sense would go up on this one, too. You can definitely see a guest's reviews, that is, if they have any. Click on the circle with the letter in it to the left of your message stream with them. That should take you to their profile page. You won't see a photo until a reservation is confirmed, but you can read their profile info and reviews there. If those things aren't there, it means they haven't filled out any info about themselves, nor do they have any reviews.
There is a guest blacklist on Facebook. I'm not a Facebook user, so can't give you any more info on that, but I'm sure you can find it.
Is this booking imminent? As in today or tomorrow? I'd phone Airbnb and ask for confirmation that the guest's payment was successfully collected. If they say yes, and there ends up being a problem, at least you have a record of their assurance that you'll get paid.