Since this stage allows 6 party members I tried to fit in as many off turn damage as possible and capitalize on free turns to trigger all the damage.
Setup
NOTE: Remove all HP passives, Bahamut Life Up and Leviathan Life Up passive on everyone.
Party 1
Laguna with LDBT. REMOVE his Ragnarok Buster Extension I and II passives! Shantoto LDCA. This can be replaced with Arciela base call
Lunafreya FR30. Raijin LDCA
Kain FR30 with 5/5 UW, Leo LDCA. The call can be replaced with any other call ability, Ashe LDCA is a decent one as it enables Terra FR to cancel enemies force effect.
Party 2
Terra FR30 with 5/5 UW. Prishe LDCA. Use Alisaie or Locke LDCA if you don't have Prishe.
CoD FR30 with 5/5 UW. Raines LDCA. Raines can be swapped with Onion Knight LDCA
Garnet with 5/5 UW, Cait Sith LDCA. This can be replaced with any other call ability.
Timestamp
0:00 Setup with Lunafreya
Reset until Luna goes first. The rest doesn't really matter. Use Raijin LDCA then swap to Garnet to use BT+, AA and Cait Sith LDCA before swapping back.
Then go into the usual rotation. After BT+, use Heavy Prayer on both Kain and Laguna.
Once done, swap her for CoD. Use Raines LDCA if Kain is not acting next to manipulate the turns. Then use AA twice to BREAK and get a free BT+ off
Kain uses BT+, LD, call and Jump. Do not use his AA.
Laguna uses call, BT+ and LD, then swap him for Garnet and Summon
7:58 Summon Mode
The goal is to have CoD take consecutive turns, swap her for Laguna to take more consecutive turns and end with swapping her for Terra on final turn of Summon for a LD.
After summon, use Meltdown, FR, BT+, Prishe LDCA, LD and BT mode
13:02 Terra BT Mode
Meltdown three times, EX, LD, FR.