My, I certainly let this thread get away from me!
Look, Hoopington, cupcake, I'm not Mormon, but I grew up in Utah. I know a bit about the Mormons and the complete, cultish fealty they demand from their members. Shunning is a big tool in their toolbox. That is what the OP is experiencing. Before he can create any kind of new relationship with his father, he must fully repudiate the terms his father is currently offering -- which are not acceptable to him, the OP. Since the OP cannot comply with his father's demands to come back to the church, then the only option is for the OP to get on with his life -- as it seems he intends to do.
If at some point his father is able to draw a distinction between having a relationship with his son and having a relationship with his son with unreasonable demands attached, then possibly there will be an opportunity for a new relationship. His father has no right to demand that his son think certain things in order to have a relationship with him. Until Dad is ready to recognize that, what chance for a meaningful relationship can there be?
Sometimes the only choice you have is how best to lose.
The OP asked for advice, and this is mine. Like all advice, he is free to take it or leave it. Sorry that is so hard for you to grasp.