All I can tell you is the Minotaurs are the challenge really (especially with the achievement-only characters). They might be easier if I wasn't sticking to the 3 characters required for achievements....
First Battle, Minotaur - Ryder/Grail talismans (So he full-heals when at 1HP - you basically have to kill him twice)
Second battle, no Minotaur, 1 hit battle (I suspect this originally had 2 Brave talismans Ox Cultists... which would have created the problematic loop)
Third Battle, Minotaur - Lightbringer Talismans
Forth Battle, Minotaur - Labyrinth Talismans
Last Battle - Icarus (Revenge), Minotaur (Echo/Shell), FIE (Space), Cosmic Wolf (Alchemy), Daedalus (Valor)
And yes, FIE seems to have a power move that will wipe out your Eddie, ending the battle, in one-shot.
The Valor's on Deadalus will remove the Immortality from Soccer Ed's Lightbringers... so it's all "chance" and "Luck" as to wether FIE will use that attack after Deadalus attacks.. and before you can use G LOL to give everyone invincibility.
On manual with my team, it's not that difficult. On auto... it's a 90% winner based on the above sentence...
FIE also seems to be immune to damage much of the time. (50% chance to avoid damage). Combine that with the fact he's a "boss" so he can't be Doomed, and much of the time attacks to remove his (blue) buffs fail... and this makes that last battle, if nothing else, a bit annoying and time-consuming.
I moved some talismans around and put a Cosmic Echo on Soccer Ed and Cosmic Life on G Lilith... that's helped. Still all chance on auto due to that last battle and Valor talismans.