According to this list, Light would be the easiest element to go with a "lots of cleansers" strategy. Alas, I only have Metis and Attar from that list, and my Attar is Lvl 60 right now (her cleanse is Lvl 65+).

Wind has only Set (SSR), the SSR Gacha Eidolon Behemoth and limited-edition Apep as cleansers. Also Limited Edition Poseidon who can block and add Thunder Resistance Up would be useful. I only got Set, and dunno about running a Behemoth friend over a Hraesvelgr one. Anyway my current Wind team (D'artagnan with Ambush, Set, Gaia, Azazel and El) can kill the 4 waves reliably, Sandalphon itself is the problem. Maybe I will sub D'art for Mordred (for her Black Propaganda and Outrage, or use BP over Ambush, as I can rely on Hraesvelgr for Defense debuff anyway). I will try and sub Azazel and El for more defensive himes, but sadly none of the Wind himes available can cleanse or block afflictions, so I'm a bit iffy on tanking overdrives every 2-3 turns or running an off-element.

For the GO, my Eidolons are: Houkei (+20% defense), Tiamat, Python (Barrier), Wind Dragoon, Rahab, Fleurety (Wind Resistance Up) and a friend Hraesvelgr (+100%, Defense Down).

I could also try and run a Thunder team next, with the same Eidolons set:

Cyclops and Indra can cleanse, and if only I had either Dian Cecht or Justitia, I'd have a third cleanser. Then run Fodla on back row as she can eat orbs every 8 turns and heal 1000HP. But then the team will lack offense, with only one slot free - and that slot going probably for a more defensive hime anyway such as Gryla, as I will still need her healing and attack debuff...

Then maybe running Mordred with Maiden's Prayer (EX Cleanse) if I REALLY want a third cleanser - feels overkill though, with Vissicitudes of Fate giving Affliction Resistance Up already. A Kirin friend could also give Affliction Resistance Up (the 3rd wave Radkiel can Paralyze as well, so I could Manual in order to always have the buff up in the 3rd and 5th wave), but I believe a Nidhogg one would fare better If I run Mordred, as otherwise I will lack debuffs - Attack debuff will be -37%, reaching the -50% cap with Nidhogg. Maybe the EX should be Trial by Jury (if running Kirin) or Cursed Chanting Chains (if Nidhogg) instead of Maiden's Prayer. The team will rely a bit on luck - pray that Blind and Dizzy procs, hope that the Affliction Resistance from Mordred and Kirin make Paralyzes stick less, and have Indra and Cyclops cleansing if needed. Heck, I speculate the damage output will be so low, I will not get to Sandalphon XD. Will test the idea against ultimate Dark Raid first, I guess.