Which version then is authoring confusion? Your reasoning seems to go like this:

KJV has "Lucifer" falling from Heaven in Isaiah 14:12
NIV has "Morning Star" falling from Heaven in Isaiah 14:12
Therefore NIV is saying Morning Star=Lucifer

No need to bring the KJV into it at this point. The NIV interprets itself by stating that Jesus is the morning star in Rev 22:16 and then in Isaiah 14:12 the NIV states that the morning star falls from heaven.

Also, please explain where Satan 'laid low the nations' before he was cast down from Heaven, which is what is implied by the KJV.

Satan laid low the nations and set man on the path that we are on when Satan said that he wanted to be like God. Satan fell from heaven before he tempted Adam and Eve (Genesis 3:1-14). Satan’s fall occurred after the angels were created and before he tempted Adam and Eve, the bible isn't any more specific.

Satan’s fall is symbolically described in Isaiah 14:12-14 and Ezekiel 28:12-18. These passages explain why Satan fell, but they do not specifically say when the fall occurred. We do know that the angels were created before the earth (Job 38:4-7).

Job also tells us that Satan still had access to heaven.

Job 1:6-7 - Now there was a day when the sons of God came to present themselves before the LORD, and Satan came also among them. And the LORD said unto Satan, Whence comest thou? Then Satan answered the LORD, and said, From going to and fro in the earth, and from walking up and down in it.

Satan had fallen (was pushed) from heaven yet he was still moving freely between heaven and earth and speaking to God directly. Whether God still allows this to happen is a matter of debate.

I'm not sure but it feels like you're very committed to the idea that there is a conspiracy here.

Are you referring to the NIV specifically or in general?

Matt 7:13-15 - Enter ye in at the strait gate: for wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat: Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it. Beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves.

Matt 7:21-23 - Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven. Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works? And then will I profess unto them, I never knew you: depart from me, ye that work iniquity.

Jesus is talking about 'believers' and he says that few will find him as the Lord will reject many that called themselves 'believers' - he never knew them. The popular / mainstream way is not the way.

Revelation 12:9 - And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.

Whole world means everyone. To varying degrees Satan has deceived the entire world (if we trust what the bible says in Rev 12:9).

There is a conspiracy against Christians and Satan is behind it. Christians are the last great obstacle to Satan on earth and he is attacking them from all sides and that includes internally. Satan mimics God and he has a counterfeit for everything that God has and he is very sublte and cunning.

Satan is also incredibly powerful - he offered Jesus all of the kingdoms of earth if Jesus would worship him. Satan would not have said that if he wasn't capable of delivering on it and Jesus did not mock Satan for making the claim.

Matthew 4:8-9 - Again, the devil taketh him up into an exceeding high mountain, and sheweth him all the kingdoms of the world, and the glory of them; And saith unto him, All these things will I give thee, if thou wilt fall down and worship me.

I say the following very respectfully and with love - Satan has deceived most Christians and I'm concerned for their salvation. I am certain that I am going to heaven and I do not say that arrogantly or boastfully. The bible is very clear on what we need to do to get to heaven. Only God knows how many Christians are saved and I am not professing to know and I am not judging. I'm am simply trying to fire a warning shot and defend the Word of God.

This video will let anyone know what they need to do to get to heaven.

I'm not a Calvanist.