It can certainly happen that characters in more sophisticated stories can "take over" as they develop and change the author's original ideas. Well, it certainly happens to me at times. ↗
As the time goes by, you change, your learn new things, your attitude is different. For the moment, I'm still enjoying ski racing so much that it would be difficult for me to think about ending my career. ↗
But I don't actually adopt the point of view that our subjective impression of free will, which is a kind of indeterminacy behavior, comes from quantum mechanical indeterminacy. ↗
Now, what that means is that there is fundamental indeterminacy from quantum mechanics, but besides that there are other sources of effective indeterminacy. ↗