I cook versions of this on the regular. I say versions, because simply having The Official Recipe is only half the battle. The actual flavours and strengths of the individual herbs and spices can vary a lot by brand, and by country, and by source, and other factors.
My main takeaway (PNI!) is that the white pepper and the smoked paprika together are the heart of the KFC flavour. The rest just augment, refine the flavour. And of course, the salt and/or MSG go a long way.
https://www.chicagotribune.com/2016/08/19/kfc-recipe-reveale...