I’m confused as to why this is confusing you. That question is being asked after Satan is finally defeated, or I should say when his defeat is manifested (he is presently defeated and earth has been redeemed from his hand, though the redemption has not been manifested). That passage is prophetically talking to Satan about his eventual imprisonment while calling to remembrance his fall from Heaven.
So....it is your opinion that when Ezekiel, speaking of the same event, says Lucifer was in the Garden of Eden before iniquity was found in him [28:13-17].....this is not teaching that he existed on a pre Adamic Earth....in the garden?
When he says that he would ascend above the clouds [Isaiah 14:12] as part of his rebellion.....this does not teach that he was on the Earth.....below the clouds?
Are you saying that Lucifer has not yet rebelled and everything we've just read is future prophecy? Is that really your position?