So, let me get this straight: The Omniscient God knew everyone from eternity who would never believe on His Son, yet at the same time he Sent his Son to die for them anyway? TO WHAT LOGICAL END, MAY I ASK?
Moreover what does God's Omniscience, i.e. foreknowledge, have to do with his Justice? Didn't he give believers and unbelievers alike "free will"?
Also, If God saved no human beings, would Satan represent the entire human race, claiming that God made it impossible for anyone in mankind to believe in Him through his Son? What case could he make? Logically speaking, since God is not morally obligated to save all, then how can he be morally culpable for choosing to save only many? Yet, this is what your premise implies. if God saves only "some", then somehow it's unfair of him if he doesn't save all? The only way God could ever be unfair is by
NOT giving sinners what they rightly deserve! But there can never be an injustice with God for giving many sinners what they DON'T deserve, since His justice has been satisfied on their behalf in, by and through His Son. Your sense of justice is totally twisted. You start with a premise that clearly implies that somehow God is morally obligated to either save no one (such as he has passed on all the fallen angels) or to make salvation possible for all.
And don't you know what Jesus taught about a kingdom that is divided against itself!? Satan hates God and hates all mankind. Satan desires only one thing: The utter destruction of all God's image-bearers. So, logically, why would Satan take up the defense on non-believers, that he so earnestly and zealously desires to be in hell with him for all eternity? Your premise is entirely absurd, sir. Satan, the hater of all mankind is going to take up the defense of those he hates!? To what end: So that fewer people he so vehemently hates get to share his pain and torment in the eternal fires of hell?
And you're also absolutely right about what you said in your first sentence. God's omniscience should not be construed as him causing unbelief in the condemned. God's "omniscience" caused unbelievers to simply remain in their own devices -- in their, natural, fallen state. And there's nothing unjust in that, as explained above.