I would agree that God knew -- He IS omniscient.
Which comes first, God's plan or God's creation of the participants in His plan? If God's plan comes first then certain things must necessarily happen, independent of chance.
I don't believe it -- I don't believe God forced Judas to betray the Christ. Judas did it of his own free will and was damned out of his rejection of God's grace.
I do not mean to mock you, but I must ask about this and every other act done by humans in conformity with God's plan: "Was God just lucky then, that Judas betrayed Christ?" If Jesus isn't betrayed, then He isn't crucified and scripture is proven a fraud. My position is that it was all ordained in the beginning.