1) AirBnb does not like to remove reviews, however since the guest cannot actually answer the various review questions regarding check in, value and cleanliness then you should have grounds for having it removed. That said, if there is someone here who has had this exact scenario and it did not go favorably then I would defer to their experience as a more likely scenario, but even then I would still fight it.
2) I certainly would not have given a full refund. You kept those dates blocked off for them and now you would be out that revenue and hoping for a last minute booking to make up for it. I would maybe do 50% if I was feeling charitable and there were other expectations that were stated and not met, but even then if they were so close-minded as to not even step foot in the place then I would probably tell them to pound sand.
I dealt with a similar situation recently. My place is in a similar neighborhood (Greenville SC) however the house is uniquely positioned on an odd shaped lot where there is actually a significant distance between itself and the neighboring properties. I only share a lot line with one guy and he is a mellow and friendly guy who says hi to the guests. Across the street is a high end condo complex, and kiddy corner there is a large lot owned by a a land rich guy who has a lot of random machinery and vehicles laying around which I admit, looks crappy, but is not a danger in any way. Other than that, there are a few outdated properties visible from my place but nothing distressed or with undesirables lurking around. I also have an aerial drone photo showing the block with easy landmarks in the photos and description, so a 3rd grader could find my exact place on google street view in minutes.
At close to midnight of the first of 2 nights, the guest sent a refund request for half of the cost complaining that she didn't feel safe and that the shower wasn't draining. Since she was right about the shower (which I later fixed) I did accept the refund request without protest, but otherwise I would've refused. In the review (4 stars), she praised what was nice about the property while also leaving backhanded comments about the neighborhood and said there was nothing to do, whereas if you walk literally 5 minutes you are at one of the most popular restaurants in the city plus at least a dozen other places for food, coffee, drinks etc and downtown is a 5-7 minute uber ride.
Moral of the story: Don't give into these guests, because even if you give them what they want they will still throw you under the bus.