My answer focused more on the "what are the options for what he originally said?" Let's examine the context. What was it that Thomas refused to believe? that Jesus was equally God as the Father is?
Did the disciples who had seen Jesus earlier tell Thomas that Jesus was God? (John 10:25)
If all the apostle knew that Jesus was God before he was resurrected, what does Thomas statement “ Except I shall see in his hands the print of the nails, and put my finger into the print of the nails, and put my hand into his side, I will not believe.” mean?
The context shows that Thomas refused to believed the Jesus was resurrected.
Does being resurrected from the dead make Jesus God. There were people in the bible that had been resurrected from the dead and no one believed that these were God. Being resurrected from the dead would have proven that that person was not God, since God is immortal.
The context show that Jesus’ statement in John 20:17 and Thomas’ John 20:28 statement show that Jesus told those who saw him resurrected that the Father was his and their (Thomas included) God.
When Thomas touched Jesus 'wounds and saw Jesus' hands, Jesus proved that he was resurrected. Thomas' touching and seeing Jesus after he died proved that he believed Jesus was resurrected, not that Jesus is God.
Jesus continued to call the Father his God after he ascended to heaven as Revelation. 3:2; 3:12 show.
There were men in the bible that were called God/god, but, as the rest of the bible shows, these men were not the only true God. Johnathan called David O' Lord God in 1Samuel 20:12 KJB, Solomon was called O' God Psalm 45:6.