If I had to guess, the sequential turn signals could be done by swapping the tail light assemblies. It's even possible it's merely reconfiguring the wiring in the connector without replacing anything. It's not likely to be more complicated than that, but it's hard to be certain. It's a single system that's involved, and the sequencing is almost certainly done within the taillight itself. Anything else would be more expensive and more complicated, with zero benefit.
The headlight, however, is a different story. For that to work, the forward looking camera and/or the radar needs to provide data to a computer which then has to tell the headlights what to do. That's a minimum of three systems that need to talk to each other. It won't be easy to retrofit that without support from Kia.