Did Jesus ever sin?

Well belief isn't a necessary component for 2 & 3 can be completely true as a fictional story. The equivalent of the One Ring that could only be destroyed at Mt Doom in Mordor.

I never waste time discussing the Bible as nonfiction with atheists, I promise I'm not going to start with you. You commenting on it at all would mean you grasp the notion.

You are incorrect about what defines sin though. Jesus did not define sin. Sin already existed prior to his arrival and its effects are felt by non-Christians. He was the perfect example to live sin free. His being perfect was based entirely on the standards established by God.

What he may have established are rules and principles, a structure, to be better followers of God's standards that he perfectly exemplified.