the question becomes for Mormons is Jesus GOD eternal or just one of 3 separate gods?
Was He ALWAYS GOD? Or did He earn His godhood?
The LDS believe Jesus is just one of three of the committee of gods (the godhead) and that he earned his Godhood before he became human but was a created being and the spirit brother to all of us including Lucifer.
I can post sources from the LDS if you would like.
The point is, the deity of Christ serves as a good litmus test.