So Satan was cast down from Heaven before Adam and Eve were created?
The devil had sinned and rejected God before he tempted Adam and Eve in the garden.
As to the expression “cast down from Heaven”, it all depends upon what one means by it. Scripture indicates Satan still communicates with God.
Job 1:6 Now there was a day when the sons of God came to present themselves before the LORD, and Satan also came among them. 1:7 The LORD said to Satan, “Whence have you come?” Satan answered the LORD, “From going to and fro on the earth, and from walking up and down on it.”
Rev 12:10 And I heard a loud voice in heaven, saying, "Now the salvation and the power and the kingdom of our God and the authority of his Christ have come, for the accuser of our brethren has been thrown down, who accuses them day and night before our God.
My way of understanding it is that Satan has been cast out of Heaven in the sense that he no longer experiences the love and joy of God, etc. … This was satan’s choice when he rejected God – rejected God’s will, rejected God as his god.
Satan is a spirit, so the “casting out” needs to be understood in a manner proper to beings who are pure spirit and not subject to time and space in the manner that is part of physical beings.