True Christianity professes belief in what Christ taught, including free will.
G-d the Son would have come into the world as true man to rejoice with His creation. He would not have come as a Savior, but to bring mankind to a most perfect communion with the Creator. When the fullness of time had arrived, the eternal Son took flesh, and having found mankind fallen, He took on His humanity the burden of the fall, for divine justice required that atonement be made to the Father, and mankind could not offer it by itself.
This, to us Christians, is very much in accordance with all that the Prophets and the Psalms wrote about the Messiah
Now of course, while mankind was not “preordained” to fall - for G-d, as Aquinas shows most clearly through reason, cannot will destruction or imperfection - it was definitely “predestined” inasmuch as the omniscent G-d knew that Eve and Adam would fall. Predestination, a great mystery, does not overcome or overrule free will, but, rather, somehow derives from it.