Most of the enemies will start by buffing themselves with defense, so most of them will be somewhat tanky, but magic damage works quite well here.
Aigaion, the main big boss of this area, can buff itself with high attack, becoming over 1100+. It can deal high ranged single target damage, or high area attack damage that can inflict paralyze. Best way to deal with it is through long range magic attacks.
Gil snappers, gunners, and great malboros can all inflict immobilize, which can be an issue if you don't have a tank, or units with long range.
Water Iron Giant is weak to missile attacks, while the dark Iron Giant is weak to magic.
After several enemies are defeated, 2 Great Malboros will appear as reinforcements. They don't have "bad breath" but will often attack with their immobilize inflicting skill.
Water Great Malboro is weak to magic, while the light Great Malboro is weak to slash.
Since there are multiple different attack types and elements, Whisper works best here as a tank, or go with a really high evasion unit. For damage dealers, it's recommended to go with magic. Sakura can deal good damage, and her Thunders Protection helps reduce damage.
The middle area can be a decent place to lure enemies, since the Iron Giant or Aigaion can end up body blocking some of the enemies from going up. If it doesn't work for you, try turtling near the spawning area instead.