Depends:
In abyssea:
You can probably ditch the maneuver set that Xiozen is always talking about, because of crour buffs and int atm. If you have +1 body you can most definitely ditch the maneuver set, and if you have +2 body I would probably just laugh at anyone who wastes the inventory space at that point.

As for gear for the pet
Taipan fangs +2 (pet Magic attck bonus +10)
Cirque earring
and any other gear that adds MAB to pet, there isnt much so dont sweat it too much.

The more important thing is atma:
MM / Beyond / Ultimate tends to be a solid combo


Out of abyssea
You may consider keeping the maneuver set it if you have no +1 or +2 body, but if you have either you can most likely ditch it.

Gear is way more important here and you will want to scrounge up as much MAB as you can for your pet since you dont get a free +80 from atma.

Healer
IF they want you to use the healer pet, theres no real gear for it as the master
For atma youll want mm/ambition/allure (or apoc) just to beef it up.

Subs
If your being asked to bring a the caster pet I assume your in an alliance and as such will never really need /nin since you wont be agroing or kiting for the most part. Just nuke 1-2 times, DAD. In most cases /sch is best for the bonus to enhancing/enfeebling skills thanks to arts, it will get you higher then blm whm or rdm and let you actually land spells.

You wont have much mp so dont get any big dreams.