The pan is getting way too much credit here, the buttermilk recipe is doing the real work. Swap that same batter into your nonstick pan and I bet it comes out 90% as good, because cornbread in general is stupid forgiving. Cast iron is a great tool, no argument, but it's not magic, it's just a big chunk of hot metal that holds heat like crazy. Your nonstick batch stuck because nonstick sprays actually burn and leave a sticky film at 425, that's a spray problem, not a pan problem. And pale edges happen on any pan that doesn't get hot enough or hold heat long enough, which is a preheat issue. Grandma's recipe plus grandma's pan is two changes at once, so you can't tell which one did it without testing.

Man that is a straight up nightmare and good on you for asking. The fact that the broker was pushing so hard when the real numbers were double the estimate tells you everything you need to know lol. Glad you walked, 60 grand is no joke.