QIf there are 5 cards on my field, including a Stack amulet with one Stack counter on it, can I still summon a Strikeform Golem with this follower's On Evolve ability?

AYes. All costs are paid before the ability is played, so the amulet whose Stack became 0 due to Earth Rite would be put into the cemetery, creating room on your field for the Strikeform Golem.