The Bible teaches against your pagan/christian religion.

I am he that liveth, and was dead

Did your god die? Jesus died. Did your god not have the keys of hell and death? Did he have to kill himself to acquire them?

You are getting stuck on the simple things. The first and the last is a title, it is not God's name. Just like Lord can be applied to multiple beings, so too can the title "the first and the last" within the context of its use.

"Looking unto Jesus the author and finisher of our faith; who for the joy that was set before him endured the cross, despising the shame, and is set down at the right hand of the throne of God."

Jesus sits at the right hand of God, not being god himself, as the author and finisher, the first and the last, of our faith. He was chosen by God from the beginning to be the end. He was chosen and he was anointed by God, not being god himself. He is the image of god, not god himself. He is the mediator between God and men, not being god himself. He is the high priest of God, not being god himself.

Jesus came to make God known to all, the true living God, the Father our Creator. These are not my arguments, these are the word of the Bible. You teach against the Bible and against the teachings of Jesus and his Apostles to hold on to a tradition that was forced upon the people by bloodshed.