Izzet Spellementals shrinks the cost of Hearth Elemental and Eddymurk Crab by filling their graveyard with cheap cantrips and Prismari Charm, so Ghost Vacuum can exile cards from their graveyard to deny the cost reduction from instants and sorceries. Seam Rip is narrower here: Eddymurk Crab has mana value 7 and Hearth Elemental has mana value 6 (cost reduction doesn't change that), so neither is a target. It can only exile a mana value 2 or less permanent like their Ghost Vacuum, which would otherwise exile cards from our graveyard. Enlightened Confidant and Essence Channeler are fragile bodies that don't block their evasive or large threats well and die to their cheap burn like Burst Lightning. Focus on disrupting their graveyard-fueled cost reduction while stabilizing with lifegain.