Pandaemoni and Sarkus, I have addressed each of those points before. You misunderstand me. Uncaused will never work. Incomplete prediction limits my information, but not my ability to act on it freely.
Whether your information is complete or incomplete has no bearing on whether you have free will at all. A computer with knowledge of everything there is would not have free will necessarily. It is merelyt another assertion that you are free to act without much in the way of a proof.
I am not sure what you mean by "uncaused will never work", though. if you are saying that your choices are completely caused, then there is no choice at all, but the effect of a series of causes. Anything else is sophistry no different than saying that when I pull the trigger of a gun and powder ignites, the bullet "chooses" to move or not move. That a human is more complex than a bullet doesn't necessarily give a human any more ability to avoid the effect of the causes acting on it.
You can't simply assert that we have real choices, you have to prove it, and until you do, either theory remains possible. If you do, however, then you are the first person in the history of philosophy to prove the reality of choice. (In which case, you win one free cookie.)
There is one out...if choice is completely caused, but humans have some means of affecting the series of causal events in advance to change them such they they bring about the choices we desires to make all along...I suppose that would do it. It would also require a bit of magic, but it's somewhat akin to the notion of the transactional interpretation of quantum mechanics, with its temporally advanced standing waves.
That is not necessarily a correct answer, any more than any of the other theories, but I can't see how to disprove it.
OTOH, if, like many compatibilists, you are saying that causes set up your desires, and then you choose to act or not act on those desires, then only the desires are caused, and the choice is uncaused--a spontaneous exercise of will that cannot be fully and necessarily determined by the prior physical states in the brain.
However, the thought experiment of the person with complete information proves there is no predetermination. God (or the perfectly informed genius) is not predetermined is he? He knows everything and had perfect predictive power, then he makes a choice as how he wants it to go. He has no "illusion" of freedom, he really gets to do what he wants, based on understanding his wants, the source of his wants, the short and long term consequences of his wants, and all that same information about is needs, and his priorities, instincts, tendencies, training, etc. He can look at all that info and say "Hey, I'm a hell of a guy" or "I'd like to improve in this and that area" and so "I'm going this direction." Caused? Yes. Predetermined? No. In the sphere of intentional action, the future won't go in a particular direction until it is either directed by volition and action or inaction. If the "real" god set it up on moment 1 to turn out a particular way, and my genius then figures out the plan, he gets to change it. That's what we can do that a "hardwired" robot can't.
Well, there is no predetermination, because quantum mechanics introduces real randomness. Under the most deterministic view of the world the universal wave function might be objectively real, and it is predetermined to evolve in specific ways, but the actual outcomes we experience generated by that wave function can still be one way or another from our perspective. Even in the many worlds view, everything that can happen does, somewhere...so perhaps one can say that there is predetermination there, but only if one takes an extraordinarily broad view and concludes "everything that can happen will happen in some universe somewhere."
Here again though, you merely assert that this omniscient being (which is already evidence that we are in the realm of unprovable assertions, since such a being cannot exist in thus universe, and this would have to be outside or separate from it) has "choice" even though he knows everything. But knowing everything doesn't give you the power to avoid anything or change anything, at least not necessarily. If the being has free will, then I believe you are right. If the being does not have free will, then you must be wrong. The state of knowledge in either case doesn't necessarily change that.
For example, the Princeton physicist Richard Gott wrote a book on time travel in the real universe, in which he runs through several theoretical scenarios, consistent with general relativity, where time travel looks like it should be possible. (They are all impractical, of course, but in theory possible.) He is very clear that, assuming the right kind of supermassive objects could be found, and if we were to use them to travel backwards in time, that there is nothing that we could do to alter the past at all. As the past has already "happened," we know that even if we tried to change it, we failed. So, if we traveled back in time, and actually tried to kill our own grandfather, we know we'd be unsuccessful.
But even as I heard him discuss that (years ago now), I hated that. I wouldn't try to kill my own grandfather, of course, but I felt like free will and my knowledge of what happened in the past should allow me to change it. If nothing else, being a jerk, after I return to the past, I would meet myself before I board the time machine and give myself a one word message, "positive"...except that if when I was boarding the time machine I met myself and my older self told me "postive", then when I went to the past, I would tell my next self "negative" (and if my older self said "negative" then I'd switch back to "positive").
Gott was very clear that even setting up oscillating timelines like that would not be stable and hence it was clear that my plan to meet myself would necessarily fail in some way (perhaps I die before I can back to the time machine, or perhaps in his worlds I'd be there and say the word "positive" and despite my plan, I would be compelled to say "positive" in each loop, or perhaps for some other reason...but my plan fails). Anything else crews up the physics apparently (at least in his view).
I tried to disprove his conjecture by coming up with something foolproof, but in the end, despite my intuition he is wrong, I can't disprove his view of the way spacetime prevents temporal paradoxes.
It's basically the same problem as you pose...but again (A) you really need to invoke the existence of a supernatural being to even pose the hypothetical, so the position is as unprovable as the question of the existence of supernatural beings in general, and (B) a supernaturally omniscient computer could know everything yet clearly not be free.
Imagine that there is a God and He is omniscient, but no being anywhere has free will, and there is predestination. Let's also assume that God starts out happy. In that case God knows the future and the past, and was happy in the past, and humans have no free will to throw a wrench into that. So God will be eternally happy, and hence God is immutable. (If God can become unhappy, then God is not really immutable.) In that view, even if God had free will, He'd never need it. Of course, once might say "but how could God be happy when there is evil in the world?", but that "Problem of Evil" (itself discussed for millennia) exists for any omniscient and omnipotent being, free will or no free will.
I suspect on a certain level you are assuming a supernatural being that is just like is (you even mention happiness), but I doubt that a supernatural being of that nature would be like us. I think the notion of our imagining such a being as "like us" is a bit strained. It's like ants looking at the kid who owns the ant farm and imagining he too must be just like them. An omniscient mind, though, would be many orders of magnitude more complex that ours is to an ant.
Still, the issue of whether such a God can have emotions or not is itself a topic that has been debated by philosophers, so again I concede that my position is not one I can assert to be true, but is rather just my personal intuition, with many other positions also being equally logically plausible.