Even if I did agree with your characterization of our beliefs (which I most certainly do not), it misses the point.
You cannot reasonably call something a heresy unless you have some definition of orthodoxy.
Likewise, you cannot say Mormons are not Christians unless you can say what beliefs, practices, or characteristics define a Christian. How do you define Christian?
Mormons who achieve the highest level of salvation will get their wives and the ability to make spirit babies as they act in a god form populating other planets. You may not like how I say it but thats the truth. If you wish to deny that there are two possibilities one you are lying, two you are not a very good Mormon.
You cannot reasonably call something a heresy unless you have some definition of orthodoxy.
But you don not need a *complete* definition. The minute you say God is alone as the God of the Entire Universe, he is as a tri-person God head eternal going forward and backwards in time you exclude mormons because they *dont* believe that. No matter how much they might agree with other points of the definition they are heretics.
How do you define Christian?
Start with the nature of God, eternal existing before time as the Father Son and Holy Ghost, perfect in nature and power and there will never be any God anywhere else. Already Mormons fail.