Ill probably be doing these as rune so the idea is buff at start aggro them/utilize some group buffs for aggro/spam flash /group them for lullaby/spam foil on cool down?
Really late reply, but yeah, just aggro > Foil.
If your team isn't bothering with sleep, then Battuta after Foil. Or if Excalibur pops, you'll want to Battuta for sure (max parry set will save your life). This is a great opportunity to floss those Turms Mittens!
Foil is enough to keep hate, for the most part. You'll want to keep it up to protect against WS spam. It's not a good idea to do too much casting/swapping, since you can get hammered in precast/midcast sets with everything hitting you.
If you don't trust your WHM, sub a job where you can Erase def-down. If you get hit w/ a WS that passes through Foil w/ Def-down on, you'll probably die, especially if it closes an SC.
Tenebrae runes are what I go with. The main NM will Aspir you dry, even w/ Lux runes up, so good to have the option of Pulsing your MP back. Light-resistance also good versus Guttler and Excalibur.
Save One For All for Kikoku (~50%-ish). Pflug > Mag Eva Set > Charm Set before pulling Guttler.
While your DD's are killing the last fomor, pop Swordplay and cast Temper... you should have full 3000 TP from all the stray hits and Tactical Parry returns. The second the last Fomor dies, drop a fat Reso/Dimidiation (should land for 50-99k) on the main NM and watch as your DD's weep because you stole the most satisfying part of the fight away from them. :)