Malarys doesn't currently have Stifle Spell prepared. Made a few other changes, too, including Lya casting Celerity and another Manyjaws and Viserys Blood Wishing a Chains of Light at the Cleric with Celerity.
[X] Revised Artemis1992 Plan
-[X] Viserys: Quickened Ancestral Awakening for Transdimensional Spell, then Searing, Agonizing, Transdimensional Firebrand on everything in the room. Then cast Celerity in order to use Blood Wish to target the Cleric with Chains of Light.
-[X] Dany uses her Sign buff to gain a +4 bonus on her Initiative, then casts a Reached, Chained Heal on all the Undead.
-[X] Richard: Go straight for the Cleric, full charge and attack, unless Viserys' Chains of Light gets him, then attack Undead
-[X] Lya: Manyjaws on all targets. Then cast Celerity and another Manyjaws.
-[X] Vee: Pronouncment of Fate on the Cleric and Alter Fortune for Viserys' Chains of Light
-[X] Maelor uses Nerveskitter on Viserys, then Voracious Dispelling on the Cleric, only if he acts before Vee and Viserys, otherwise Eldritch Blast some Undead
-[X] Malarys uses his Sign buff to gain a +4 bonus on his Initiative, then readies an action to use Greater Dispel Magic to counterspell anything the Cleric attempts to cast.
-[X] Waymar moves to protect Viserys and Lya from the aftereffects of using Celerity.
-[X] Garin uses his Shadow Jump and Shadow Pounce abilities to attack the Cleric once Viserys casts Firebrand.
-[X] Aradia attacks any guards she sees attempting to enter the manse from outside.