Keep in mind I can't see any of the pics on the website you pasted. First and foremost is try to pull an accident report, make sure both are clean. Vehicle specific is to see if both front seats are cooled. If only driver is cooled then you are like me and your car was built pre-October 2014. After that both seats will be cooled. Lister for engine rattle at start-up. If you hear it and don't like it, take a pass. The rattle is not dangerous to our engine and Kia says it is within spec but be aware, it is a thing and presents itself more when it's colder. Take it for a ride and listen for flexion in the roof. Sometimes our soonroofs pop/squeal. It's not bad on my car but I can hear it sometimes and it doesn't sound the nicest (almost cheap). This is my first car with a full glass roof so I'm not sure if that's just how it is or not. This is best done when ingress/egress of a curb at an angle (don't pull in straight).
If these are SXLs take a look at the tires, the chrome on some of these peels off. Look at the map/software version that is on the vehicle, they may be way out of date, if they are then try to get the dealer to upgrade them for you. The map software for these cars aren't cheap so try to get the dealer to do it for free (not add the price into the car). Do a test drive at highway speed and make sure roof seals are good, some people had a problem with this. Also listen for whistling with the side mirrors, if you hear whistling then it should covered under a TSB. Fully open the sunroof and listen to the action, it should be smooth with no interruptions. Also, while it's open, check the seals and make sure they look good and not flattened 1 direction or another.
In general be aware that our engines are a bit sooty and in that regard if you like to keep a nice looking car you'll need to wipe the exhaust ports down probably about every week or so. If your car is rolling on the original tires people don't much care for them so you may want to look into upgrades, you guys get a bit more weather than we do down here (you're our top hat!). Other than that just do normal used car diligence. The things I listed above are just things I've heard over the years, most people will experience none to some of these while a few have experienced most or even more lol.