12 Mythos Mission...

[Anima]

In my opinion, It was easy as any Job. I was soloing it, since when I started most I know were done or already in the Stone area.

As a DRG, you have a x2 Chance of Mitigating Damage [Decoy+Dread Spikes] (1min+ Timer).
As a PLD, you have High HP & Defense and Invincibility Skill. (15min Timer), etc
I'm thinking everyone who does this would switch to DoW/M and won't go as DoH/L

Skills & Abilities are more like precautions when there are no other ways / you get caught.

Riding Chocobos will out-run most enemies without them being able to dish out any type of attacks; Morbol, Drakes, etc.

Knowing Mobs' Aggro type and figuring out the safest path is very helpful.
Knowing when to walk when an enemy is "Sound" Aggro,
Run behind when "Sight" Aggro or Figure out his "Aggro Sight" angle
Avoid them entirely or bust right in using Skills when enemy is "True Sound/Sight"
Knowing their "Range of Attack"
Figuring out their "Distance" of Aggro also helps !

EDIT: Just thought I'd mention, If you want, you can go through the trouble and start a leve and abandon where you can get it. Leve resets all Ability timers.