Bit late but
here is a chart of damage you can expect for given res. Also remember skills like devotion will drop your res.
The stamina would've just went to Daily Dungeon if I finished, no real loss.
Yeah I went in kind of cocky with most of my White Dragon Advance/Retaliate team, except I put Tyro and Eiko in for abilities (removed Cecil and Rydia).
I'll give it a redo soon with a smarter setup (all high RES gear) for a slow burn.
Draw Fire on Cecil could take all the in between hits if he stays in Defend, Sentinel Grimoire's and Shellga would salve subsequent Megaflares (or maybe Boon and Magic Breakdown for the added Haste). My issue here would be mild MAG output, I have two 8x Biora and 8x Comets (plus a 4x Bioga), but no standout MAG weapons.
Sooooo, hmm.
Cecil: Draw Fire and Pound.
Rydia: Biora and Comet.
Viva: Biora and Bioga.
Selphie: Curaga and Faith.
Garnet: Curaga (Shellga?) and Dispel.
Friend: Sentinel's Grimoire.
I could put my shared Shellga on Cecil to take two Curaga (probably important) and Pound can be used after Dispel, which can trigger extra self-Flares since Magic Break won't be useful with resist.
Faith is probably a must thanks to lack of 5★ MAG.
This might work if I can take another Megaflare before Shellga Soul Break and dude reliably Flares himself.
If I can't get that to work, I'll just have to wait to see if somebody more clever concocts a strategy, egg Tellah and Golbez to 65 (a mere scratch considering the recent event), pull from the current banner and leave luck to Heaven, or skip, since the reward is honestly not amazing (yay, materials and golds, those aren't in the dailies or anything).