Well as a responding non-Catholic, I'm already disproving your expectations, FWIW. And one of the main reasons I'm not a Catholic is, as a matter of fact, related directly to this question. Free will seems fairly important to me - without it, we're mere puppets who live, suffer and die solely for the amusement of an insane God. On the other hand, the disparity of initial birth conditions is so extreme that any concept of free will is reduced to how well we face difficulties which are sure to destroy us, versus having any hope of actually being on control of our lives.
That's why people who are so proud of how they've "built" their lives through hard work and discipline amuse me so much. They so easily discount those who have exhibited just as much - if not far more - of these attributes and still "failed" in the eyes of the world, for any number of reasons. No, in the end, free will can only mean the freedom of choosing our attitude towards our lives, as exhibited in our actions. That's it. The results are entirely up to God.
This isn't a "belief," it's a simple, obvious and enormously evident fact that exists in millions of ways all around us. And I'll prove it - do you have to pray and give thanks for your successes? Why, if YOU did it? Because in fact, you didn't do it. You made the proper effort, even a lot of effort. Even enormous effort. But you didn't make your success, and you know it. You know things could have gone the other way despite your efforts - you know it in your heart, mind and experience.
So success is a divine gift each and every time it happens. And yet, God's law also includes the simple fact that making right effort enormously increases the chance we will receive success in return, and studying what succeeds leads to even more probability of success in the future. So it's truly a mystery.
But is it "free will"? Because it's all we've got. Personally, I don't really care whether it's free will or not. It is what it is, and by acknowledging it and respecting it I become a better person. After all, it's not like anyone is going to survive this place, so what's the goal here? If living a certain way brings the most possibility of peace and prosperity and learning and happiness for myself and others - and prepares me more and more for facing whatever comes afterwards - then I call that the right path.
"Belief" is merely a word. How we live our lives is our true belief in God. And in the end, not knowing how things will turn out but still having to make proper effort, is that not the very definition of faith? So could this whole mystery be created by God in order to require us to learn what true faith is by having to live it? And learn compassion towards others dealing with difficulties despite their best efforts?
As for the philosophical definition, since determining the existence of "free will" as it is displayed in the world is inescapably dependent on understanding why the initial conditions are so different for each child born into this world, it's a term that simply cannot be determined philosphically unless you want to include reincarnation. There's just not enough in one single lifetime to explain those innate differences.
Now don't get your hackles up. Personally, I like reincarnation. Looked at from the soul's point of view, it means there's only one life with many chapters, and God wins over each soul no matter how long it takes for them to learn. And it explains free will plus different birth situations, and it doesn't get rid of hell or heaven. Granted, hell and heaven aren't eternal, so there's that. And ultimately the goal is union with God, not just living in a heavenly realm.
So I think it's beautiful, because it gets rid of the eternal punishment for limited sin thing and solves the birth differences thing. But I am also very aware that most Christians don't share my view and, fortunately, I have no need to try to convince them. Because in a very practical way, it's not necessary to live our lives properly. We still have to make the correct effort, on faith, and God still dishes out the results.
Oh yeah, here's the Bible verse required by the question: "This is the one ... there has not risen anyone greater than John the Baptist ... And if you are willing to accept it, he is the Elijah who was to come. He who has ears, let him hear." (Matthew 11:11-15)
A) Free will doesn't exist
B) Limited /conditional free will exists
C) Unconditional Free will exists
D) Something else entirely (Please explain)
Thank you for your participation.