The Treason of Isengard: Eru's Plan?

[burrahobbit]

We've no evidence that he would choose pacifism

Of course not. Feanor would never choose pacifism, but that isn't the point. What I am trying to say is that a person can not possibly be free to make moral decisions in a deterministic universe. The two ideas are incompatible. Either a person has a fate/free will or he doesn't. There may be some wiggle room, but if there is no possible way for you to avoid certain outcomes then you do not actually have a free will, and whatever the outcome is it is the desire of whoever/whatever it was the made the decision. The deterministic cosmology of Middle-earth is the land of the Turing Machine.