Did Satan unwittingly create his eternal punishment by instigating the fall of man?

God is, as you mention, omniscient. However, something in your question hints that God somehow wanted men to fall. If that question should ever come to your mind, just remember that Christianity preaches that Jesus (God, The Son), suffered a horrible death to save you. This should quickly clear out any doubts regarding God's true intention as it plainly reveals that God wishes nothing but the happiness and joy of His creation.

Now, back to your question, God needs to allow for a certain degree of freedom in us in order to allow us to love Him. Think about this. Let's say a guy meets a girl and falls in love with her, so then he proceeds to kidnap her and lock her up in his house, he marries her in secret and they live together until either one dies. As ridiculous as this may sound, true love cannot exist in such scenario. For true love to be possible, the girl has to be able to leave, or choose someone else, or cheat, or just not date him, and, being able to do all these things, she freely chooses to stay with him.

God doesn't really need us to love Him, He wants us to, but His glory is not affected simply because we choose not to. BUT, it is US that need to love God. God is love. Christianity teaches that true fulfillment in life comes from the exercise of charity and love. If God hadn't put that tree in the garden of Eden, the scenario would be like that of the kidnapped woman, unable to leave. However, in order to make us truly happy, God let us disobey, and when we did, He came to rescue us from out mistake at the expense of His own life and suffering.

The Bible is only a partial map of God's whole creation (universe) in that The Bible provides us with very little information about other worlds/realms and other creations and occasionally shows us that other creations are able to move into this world but not vice versa. Yet The Bible is sufficient for us and this world. So at best we can only speculate/debate on the other things. In this case The Bible's narrative gives us some hints that Satan already knew about the tree because Satan's first words to Eve reveals that. So more likely Satan and his cronies may have taken the fruits of the Tree in another realm and moreover also from the Tree of Life and thus injected evil into themselves but at the same time negated the side effect of the fruits (death) and achieved immortality. So having lost God's trust in their realm the next thing Satan and his cronies would want to do is to gain allies and numbers. Thus the generous advice to Eve. Here, an important thing is that the sly Satan never told Eve to also take the fruits of the Tree of Life. Once the fruits were taken, the cascading/butterfly effect started including the arrival of sin and death and the domino effect continues to this day till the end days.

God is omniscient in that God can surely preview everything and every possibility to its end, infinitely more than a programmer who created a program and claims to know its every logic, or a chess master who begins a new game and tries to model all possible moves and endings. God already saw the future and gives us a view of it in Revelation. The thing is that because God already knew it, God also gave the warning beforehand in Eden, then gave us the commandments generations later, and finally God gave us Jesus Christ and the Revelation. It was up to Adam and Eve to not take the fruits, and it is up to us to accept Jesus Christ, but then God already knows who will and who won't, but then again we don't know. The decisions/actions we take are ours because we have the freedom, but God already knows our actions/decisions but God didn't/doesn't make them. God already knows the endgame but the moves we make are ours and ours alone, and it's up to us to be held accountable (judgement) for our moves or instead move in sync with Jesus Christ and escape the accountability, but then God already knows who will and who won't. God 'knows' doesn't mean God 'wills' it, 'knowing' and 'willing' are entirely different. So Satan's actions/decisions are Satan's and Satan's alone though God may have already previewed it.

PS: I understand this to be a general category, so please forgive me if my way of answering is wrong.