Based on some suggestions from some readers of this blog, I lightly grilled two habanero chiles and one medium size jalapeño chile, put them into a blender with three cloves of garlic and two cups of buttermilk. I processed this mixture and used it to soak my chicken pieces. I was pleased to discover that, yes, this is a way to add 'heat' to the chicken flesh proper. It worked. One commenter had noted that based on their experience, to get this heat one needs to add much much more chile or black pepper or cayenne than one would think one should. And that is how to infuse the chicken with chile 'heat'.
Thanks to Dana LeJune and several 'anonymous' commenters for the guidance.