Technically his partners on this stage doesn't require evasion since all the attacks are single target. You could bring Cissnei and utterly demolish the enemies.
Timestamp
Party setup at 11:07
Celes LDCA can be used over Zack
For the other calls you can use anything else. I don't even know why I bothered with thunder enchant on Ashe.
0:00 Setup
The idea is to launch both Freya and Kain into the air, but swap Freya for Laguna when she comes back down. By that time the enemies are all Locked onto Shadow Via a Zack LDCA so Laguna is safe.
Have Laguna use BT+ and LD then spam AA to bring back Freya.
5:53 Shadow full damage phase
One wild throw triggers double Lancet and Desperado :)
7:11 Summon Mode
Mainly to dispel the enemy buffs via Diabolos summon