Sorry, but the historic Christian church has taught that Christ never stopped being man. He is the everlasting God-man.
I am Christian, and that's news to me. Where in the Bible does it state that Christ is "the everlasting God-man?"
The concept of the Trinity contradicts this.
Clearly God is changeable (at least in form), but you say that He isn't. I am curious as to why you would side with the Mormons on this issue.
A changing concept of right/wrong belongs to politicians, not supreme beings.