Keep in mind that you don't need to do the Nightmare immediately. You can complete it any time the Nightmare Dungeon is open. So I'd focus on making you team stronger overall and come back to the WHM Dungeon later. It's my understanding that the WHM one is overtuned and a lot of people struggled with it since people don't have multiple copies of WHM abilities. After all most people don't take more than one White Mage on their team.
Depends on if you have Agrias in which case you still have a better Pecil. Aaron's SSB really is much better.
I really like Faris. We just skipped the event which would have given us her MC2, though. Faris has a super wide ability and equipment selection - Thief5, Sup5, Dancer, etc. makes for some really fun combinations. Like Ramza, she's equally good as a support or something else entirely.
WHM Nightmare is a classic honey trap. I'll save my orbs, thank you.
Auron's SSB is a really good stacking debuff (ATK/DEF) that fits really well onto melee teams. Pecil gives you a strong Paladin (Pro/Shellga hybrid character) with great tankiness. I prefer Auron between the two - it's Pecil's BSSB that is arguably #1 in the game.
There is a bit of power creep and you are playing catch up. Cloud is one of the first characters you receive and you should use him heavily since he can use an ability called retaliate. Activate retaliate and have your weaker characters attack him and he'll attack the enemy. You can use this method to complete some content you wouldn't otherwise. There is also abilities called double cut and tempo flurry you should look into crafting. They attack twice for reduced damage, but if you aim it at Cloud when retaliating, he'll just attack twice. Get rid of the core classes ASAP they suck.
