For logic to be respected we need to specify all the assumptions to the best of our abilities. Also there is no point in assuming that God's omniscience includes knowing something that is not knowable.
In addition to assuming that God can know future events, we need to agree on a premise that there actually are future events that can be known. We can't use a belief in God's omniscience to guarantee that the propositions that we happen to come up with refer to anything real.
This is nothing against God's omniscience nor even against God's existence.
Michael Dummett made a similar point in presenting arguments about realism and anti-realism: (page 351)
It is a persistent illusion that, from the premiss that God knows everything, it can be deduced that he knows whether any given proposition is true or false - that is, that he either knows that it is true or knows that it is false, and that his omniscience therefore entails that the proposition is either true or false. On the contrary, its being either true or false is required as a further premiss in order to deduce from his omniscience that he knows, in the sense stated, whether it is true or false.
So the assumption that "God knows the future" requires an agreement on another premiss that there is a future that God can know. One cannot argue for this premise by claiming that God's omniscience guarantees such a premise to be true. Omniscience does not require knowing what isn't there to know.
Michael Dummett. The Logical Basis of Metaphysics. 1991. Harvard University Press
