Ultimate Necrophobe was a joke. I found the 3 Pigs a more challenging fight because it abuses all of RK's annoying design quirks.
Set up for Ultimate Necrophobe:
Bartz: Rune Axe++, Genji Helm (FF6), Omega Badge, Fira Strike R3, Blizzara Strike R4, Attunement II
Exists to nail two weaknesses and can do so reasonably hard. Genji Helm for the added Res boost soul break insurance.
Faris: Aevis Killer, Edin's Coat, Vossler's Gauntlet, Magic Breakdown R4, Full Break R2, Dragoon's Determination
Stat buster, pretty straight forward, has an MT Soul Break to help in the first part if that lasts too long, also lowers his defenses in the 2nd half a bit while being reasonable damage.
Tyro: Darts+, Gaia Gear+ (FF6), Godo's Mask, Lifesiphon R4, Carbuncle R3, Dr. Mog's Teachings
As usual, his damage is not really meaningful (1300~ with Lifesiphon), pure utility. Opens with Carbuncle to shut down a large part of the first phase, Shield Grimoire afterwards, spam Lifesiphon so I can get SG's reused.
Yuna: Lullaby Rod, Priest's Miter, Yuna's Obi, Curaja R4, Shellga R2, Mako's Might
Healer, has Shellga because it helps a lot here, Priest's Miter for the death resistance, HotF for my MT Healing and Heavy Regen even helps with Reflect up. Uses Basic physicals mostly in first phase for gauge gaining since she can't heal. Amusingly, I did cast Curaja near the end of Carbuncle on Terra once, ended up healing him, which was enough to ruin a DRAMATIC SYLDRA FINISH!!!!! by Faris meaning Bartz had to finish him off with a generic Fira Strike, ruining the moment. Ah well...
Terra: Maduin's Horn, Minerva Bustier, Terra's Pendant, Thundaja R3, Meteor R2, Devotion
Exists to nuke the first phase with Meteor, Thundaja to hit the 3rd weakness in the 2nd half, with occasional Magitek Missile Soul Break (13-16k depending upon what Debuffs are up, so yeah, better than Thundaja which was just 9999) Minerva Bustier used because it's Magic is almost Armlet/Hat level but the defenses are substantially better.
RW: Oerba's Boon. I lacked Protectga, and it's extra healing during Carbuncle, so ideal fit here.