I have a tow bar on my car. I don't have any electrical hookups at all.
When you say to carry your cycles it is rather an descriptive statement. Are you looking at pulling a trailer that will require an electric hookup for brake lights?
I know there are going to be those who say that just because the manufacturer says that the car is not designed for towing, that hooking up a trailer to your vehicle won't void the warranty as Kia would have to prove that the hitch caused the problem. I take a different side in I do not want any modifications to the electrical so that I can clearly show that the hitch on the back of the car is used exclusively for a bike carrier and cannot be used for anything else so there is no doubt that I wasn't pulling a heavy weight behind myself.
When I first saw this post, I misunderstood. In the US, a towbar is attached to the front of the car and used to tow the car behind something else, such as a motorhome. I see you're asking about a towing hitch attached to the rear of the car.
Since you are not located in the US, I can't say for sure what Kia says you can and can't do as far as towing goes. Here in the US, they do not recommend towing at all. That said, we also have laws that say they can't use the fact that if we tow something they can deny warranty coverage. They (Kia) would have to prove the towing was the cause of the problem. I thought in Europe that Kia allowed towing based on weight and equipment.
I wouldn't use a Niro to tow anything that was heavy enough the trailer needed its own brakes, so it would have to be real small and light. If you are only connecting a bike rack to a lightweight hitch, I wouldn't think extra lighting would be necessary, unless the bikes are blocking the car's rear lights.