Foresight is up. Moves 6 squares south and 5 east, placing the echo 5 squares north of his final location (OI think that puts me next to the southern one and the echo next to the eastern one).
Once everyone is ready, he drops his banishment spell and attacks with his readied attack.
All attacks with advantage from foresight, elven accuracy, lifedrinker, and great weapon master. If the southern one falls, move the rest to the eastern one, attacking through the echo.
Readied attack
(1d20+9)[19],
(1d20+9)[21],
(1d20+9)[20],
(2d6+24)[27]
Attack 1
(1d20+9)[26],
(1d20+9)[14],
(1d20+9)[20],
(2d6+24)[31]
Attack 2
(1d20+9)[17],
(1d20+9)[27],
(1d20+9)[27],
(2d6+24)[28]
Uses Action Surge
Attack 3
(1d20+9)[17],
(1d20+9)[17],
(1d20+9)[15],
(2d6+24)[36]
Attack 4
(1d20+9)[29],
(1d20+9)[22],
(1d20+9)[14],
(2d6+24)[31]
Any Crits in order
(2d6)[3],
(2d6)[10], (2d6)[11]
If any Crits, also add 5th level Eldritch Smite
(12d8)[42] = total of 198 against AC17.
Spoiler: Foresight
Show
Casting Time: 1 minute
Range: Touch
Components: V, S, M (a hummingbird feather)
Duration: 8 hours
You touch a willing creature and bestow a limited ability to see into the immediate future. For the duration, the target can’t be surprised and has advantage on attack rolls, ability checks, and saving throws. Additionally, other creatures have disadvantage on attack rolls against the target for the duration. This spell immediately ends if you cast it again before its duration ends.