Christian Philosophers and Divine Agency

My philospher friend Mark Case (Ph.D. Cornell) and I had a short discusssion the other day about the nature of free-will. Apparently, the majority of Christian philosophers, following Alvin Plantinga, tend to think that human free-will is not compatible with the kind of determinism that states that if one could know everything about the universe, then one could predict any future event. But where would this leave the likes of Jonathan Edwards and his position on free will? Edwards seemed to say that God does have such perfect knowledge, but that humans still do, in fact, have a kind of free-will in the sense that they can always choose in favor of their preferences. Is this just too shallow a sense of free-will to deserve the name, according to Plantinga, et. al.? In a somewhat related observation, my nagging sense has been than we don't know enough about the nature of divine agency to state, philosophically, that God can't determine a human decision without violating all senses of free-agency in the human chooser. Isn't it conceivable that God could act on an object (like a human will) in a way unlike ways that we would (such as coercion, brainwashing, etc.) and thereby allow that God can foreordain (in God's way) a human choice that nonetheless allows that choice to still be called "free"? Isn't it a potential err to make quick analogies between zero-sum events of agency in the world of our normal experience with what need not be zero-sum events when we're dealing with an agent like God who gets his work done God-knows-how? I need to think more about this (and my later post on Molinism goes deeper into this issue).