This is a fair price for a car in fair condition. It is a good deal if you are looking for a deal, but with a history of accidents, you are starting off already on a bad foot. Once the warranty runs out, you are on your own and hidden problems become pricey.
Interest rates vary by location, so you just need to get some quotes around you.
Check exterior, interior, doors, sun visor, seals and trim, suspension, seat movements, screen defects, charge port door opens/closes. Make sure they include the tow hitch.
Tesla will only fix flaws not disclosed in the pictures. Upon delivery of my used XP90DL, there was a crack in the windshield and dents on the hood. They fixed those for me because it was not observed in pictures. They usually are very good at pictures. If there are any flaws, it will have it's own picture so that you see what you are getting. Those pictures make those points of concern you pointed out look just like variations of lights and other background images from the reflections off the car. The last pic is not where the door rubs against the car. THAT issue is on the frame of the car in the area above the back tire.
You do not lose shipping fees if you decline (as you did not accept it). This is what my delivery center had discussed when I talked about the possibility of refusing.
Free supercharging has been taken out if purchasing from Tesla (but not from 3rd parties)
AP is usually unlocked for all used X's