I still can't grasp what you are getting at regarding free will. Our nature/nurture inclines us to behave in a certain way, but we still have the ability to comply with that inclination or go against it. How is that not free will?
If you decide to go against your habitual inclination, there will always be some underlying reason why you chose to do that, even if you aren't consciously aware of it.
I can do it for the very simple reason that I want to show that I can. I am NOT bound to follow my natural inclination ... I can act contrary to it ... and that is free will. Everybody has that ability.
A choice made for absolutely no reason whatsoever, would be a random choice, and therefore nothing to do with 'will'. In fact it wouldn't be a choice it all, it would be an accident.
If I am out for a walk in the woods and come to a fork, I make a random choice as to which branch to take, but I wouldn't describe it as an accident.
We can never be free of cause and effect.
I suppose not, but we still have free will to dis/obey the cause. If my head itches, I can either scratch it or not. That is free will.