It's interesting that Christians put so much weight on freewill, but the Bible destroys their argument for it.
The Evangelical concept of free will came about because god wants you to serve him of your own free will. This is a choice that you make. It is very important that god is not forcing you to serve him. In the confusion about free will, I admit that I believe in it. The rapist has the free will to rape you, or not. The murderer has the free will to kill you, or not. Driving home and having my supper in mind I know exactly what I am going to fix. Then I get home and fix something else.
I think free will and determinism are both misnomers. You post suggests that the notion of determinism has very limited predictive power.
It's a different argument to be made about freewill in general and freewill under the specific condition that you were created by an omniscient God. Especially when the book explicitly says your path is predetermined.
I think that the post is not so much about the debate over whether free will exists or not, but rather about whether the Christian position on free will is self consistent or not.