Big time fried chicken guy here. Brine is very important for juicy, delicious chicken. I've never had a problem with my chicken in buttermilk for 48ish hours, but I would go for a minimum of 12 hours. Yes, season the crap out of it. Salt, pepper, garlic powder, onion powder, chilli powder, whatever... It's up to your tastes

The breading is also 100% to your taste. Extra crispy chicken, I like to coat in a mix of flour, cornflour, and seasoning.

But I also cook the chicken a little first (180c for about 5 mins), then while it's hot, I dust it again, and then re-fry at 220c for a few mins. I find this makes it extra crispy.

To get to this point, I've fired a lot of chicken. I've tried a lot of things. So with that, I don't know everything cause I haven't tried everything. So be ready to make changes and try again and again till you find what you like