[GBF/グラブル] Super Ultimate Bahamut (SubHL) Dark Execute 10% No ES Yatima / スパバハ 闇 １０ヤチマ 永遠の落款 なし 

There's no ES or Yatima here but on the otherhand you're REALLY reliant on Earth Tenent being 0. You also have to put out as much skills as you can without ending the 50% omen otherwise the boss gets the Unchallenged buff or you'll lack the dmg if you don't use skills.
Six is replaceable with Predator, H. Lady Grey (if you have yatima and ES), Bowman (same thing with Lady Grey)
Y. Ilsa irreplaceable
S.Meg same thing with Six but you'll need Six to be 150 or an ES or two and Yatima