A quick summary sheet that I made for the Twin Attendants, since it's difficult to keep all of their stuff straight. This is mostly focused on party and DPS buffs they can grant.

I've also included some mnemonics for helping me remember the elements used by each role, each of which uses starting letters for 3-4 of the elements.

Twins Summary Data

Buffs at skill level 10 @ 100 Desire

Element Combos

Fire Ice - Mischief Innocence - Jack Bros

• S1/2: Increase party attack 39.0% x 3 turns
• HL: Increase party attack 24.4%, damage 34.2% x 2 turns
• A2: Increase party Attack 30% x 2 turns

Elec Wind - Service Admonition - Agathion & Sudama

• S1/2: Group heal. Decrease party damage taken 19.6% x 3 turns
• HL: Group heal. Increase party max HP 9.8% x 2 turns
• A2: Decrease party damage taken 20% x 2 turns

Psy Nuke - Absurdity Nonsense - Onmoraki & Mandrake

• S1/2: Increase twins & other DPS pierce 9.8% x 3 turns
• HL: Do ST damage. Increase twins & other DPS attack 34.2% x 2 turns
• A2: Increase twins & other DPS crit dmg 20% x 2 turns

Bless Curse - Luck Loss - Bugs & Shiisa

• S1/2: Increase twins attack 29.2%, dmg 19.6%, CR 9.8% x 3 turns
• HL: Do AOE damage. Increase twins attack 29.3%, crit dmg 19.5% x 2 turns
• A2: Increase twins skill damage 10% x 2 turns

Roles

Medic: Fire Ice Elec Wind (FEW / WIFE)

• Increase twins healing 21%
• Increase party dmg 24%
• S3: Group Heal. Increase party dmg 43.9% x 2 turns

Strategist: Fire Ice Psy Nuke (FIN)

• Increase twins speed 5
• Increase party attack 30%
• S3: Increase party skill amp 14.6%, crit dmg 19.5% x 2 turns

Sweeper: Fire Ice Bless Curse: (FIB)

• Increase twins CR 15%
• S3: Becomes AOE attack

Guardian: Elec Wind Psy Nuke (PEW)

• Increase twins shield 21%
• S3: Grant party shield. Increase party defense 48.8% x 2 turns

Saboteur: Elec Wind Bless Curse (WEB)

• Increase twins speed 5
• Increase foes' damage taken 24%
• S3: Inflict Shock, windswept, and 2x curses. Gain 2x blessings.
• S3: Decrease foes' defense 50.8% x 2 turns

Assassin: Psy Nuke Bless Curse (NBC)

• Increase twins crit dmg 30%
• S3: Extra almighty hit
• S3: Twins gain 4.9% stats from other DPS x 2 turns