We can't answer that question without stuffing God into our finite conceptual box of either or world. Just as with certainty we cannot say whether light is a particle or a wave because it exhibits the characteristics of both. Our "working model" of God is too limited to speak of in any degree of certainty. We Orthodox call it a divine mystery.
God's plan is to save mankind. We know that much. How mankind came to be in need of salvation is a different story. Did Adam have to sin? Did God make him sin? Did God create Adam knowing that he will sin or did God create Adam wanting him to sin?
The choice is ours and God knows our choices. He doesn't make our choices. He created us. He did not pre-program us.
The problem with God predestining our choices is that He would be the cause of our evil as well. The transcendental God knows how we will end up because for Him time is not a developing story. He sees us at the Final Judgment and at this moment as well—all at the same "time."
He knows my choices, I am sure, but He does not have to "wait" and see what happens with me. Yet, I can assure you that He is not typing these words by forcing me to type them. Nor is He forcing me to go to church... :)
The issue is that God knows everything. Therefore, God knew with absolute certainty that Adam would sin. Knowing that, God created anyway.
Adam sinning, once creation was initiated, was an absolute certainty. If God is omniscient, there is no escaping this logic. It is certain.
The choices of every human, because God made humans that way, are based on the individual's own will. ALSO, As you said, God's knowing is not the same as God's forcing. Therefore the choices are foreknown by God. They are not forced choices in the sense that God was an accessory to sin. They are, however, predetermined choices in that this world was created with total knowledge of all that would transpire.
Therefore, God is not a participant in sin.