Sorry this took so long. Lots of stuff to think about, then had to walk the dog, then my sister called asking me to help her figure out how to use a Kindle, then I had to type it all up...
This covers most everything I can think of. The Vilderavns should all be petrified unless they're really unlucky (Nat 20 on their saving throw), because otherwise they'll almost certainly die to Fire and CON damage. The Jabberwock has enough HP that even tanking the SotD, Viserys' Maximized Clinging Searing Fire Breath, and getting pounded on by the Greater Black Tentacles will still leave it with a bit of a buffer, unless it is also Petrified, which is actually a serious possibility.
Everything after Viserys' action is just gratuitous.
[X] Plan No Hesitation
-[X] Viserys casts a Maximized Time Stop spell, gaining 5 rounds.
--[X] 1st Round: He targets the gathered Fey and the Jabberwock with a Greater Black Tentacles spell.
--[X] 2nd Round: He uses Ancestral Awakening to learn the Delayed Spell Metamagic then casts a Arcane Spellsurge as a Swift Action.
--[X] 3rd Round: He casts True Casting as a Swift Action followed by a Delayed Maximized Potent Mythic Shadow of the Doom spell using Wild Arcana while using all three charges from his ring (36th caster level to overcome Spell Resistance, DC 37 Fortitude save to avoid being Petrified, or 216 points of Searing Fire damage, plus 6 points of STR, DEX, & CON damage [-66 HP to each Vilderavn and -78 HP to the Jabberwock] on a successful saving throw) targeting the Fey and Jabberwock and their surroundings.
--[X] 4th Round: He casts True Casting as a Swift Action while flying over the gathered Fey and Jabberwock.
--[X] 5th Round: While directly overhead, he uses a Maximized Clinging Searing Dispelling Fire Breath positioned to envelop all of the Fey and the Jabberwock then quickly returns to his position with the party. They won't suffer damage or be subject to Dispeling, but as soon as the Time Stop ends the Clinging Breath will inflict 120 points of Searing Fire damage.
-[X] When Time Stop ends:
--[X] Viserys activates his previously cast Shadow of the Doom spell as a Standard Action and targets the Jabberwock with Freezing Glance (DC 30 Will save) as a Free Action. He Counterspells using his Ring of Spell-Battle and Battlemagic Perception buff, or uses Wings of Cover as necessary. If necessary, he uses one Mythic power to activate Amazing Initiative plus his Belt of Battle to gain an additional Standard Action to cast a spell, reserving Celerity for an emergency.
--[X] Richard acts to defend Viserys as necessary.
--[X] Vee targets the enemies with a Rain of Roses spell. She Counterspells using her Ring of Spell-Battle as necessary.
--[X] Zherys targets a surviving Vilderavn with Greater Shadow Enchantment to duplicate a Feeblemind Spell (DC 30 Will saving throw) as a Standard Action after Vee casts Rain of Roses. If any others survive, he casts Arcane Spellsurge as a Swift Action, then casts up to two more Feeblemind Spells, each as a Swift Action, targeting Vilderavns at his discretion. If no Vilderavns remain, he instead Blood Wishes an Assay Spell Resistance spell as a Standard Action, casts Arcane Spellsurge as a Swift Action, targets the Jabberwock with a Mindfog spell as a Swift Action, then Feeblemind as a Swift Action. He uses Wings of Cover to defend himself and nearby allies as necessary.
--[X] Maelor targets a surviving Vilderavn with a Maximized Mortalbane Noxious Blast using 3 charges from his scepter (66 points of damage and DC 26 Fortitude save to avoid being Nauseated). If none survive, he instead targets the Jabberwock.
--[X] The Myrkdreki and Mind Dragon each target the Jabberwock with Touch of Idiocy spells (1d6 INT, WIS, & CHA damage) using Spectral Hand (and Shadow Enchantment in the Myrkdreki's case). They use Wings of Cover to defend themselves and nearby allies as necessary.
--[X] The Erinyes fan out and focus fire any surviving Vilderavn, while Mereth targets the Jabberwock with her full attention. If no Vilderavn survive, the other Erinyes focus their attention on the Jabberwock.
--[X] Amrelath casts Bloodwind and targets any surviving Vilderavn before directing remaining attacks toward the Jabberwock. He uses Wings of Cover to defend himself and nearby allies as necessary.
