1- How do you get "final attack" Materia?

1. It is a Chocobo racing gift at the Golden Saucer.

2. I think if you just have to use it a lot.

3. You have to know the level 3 limit break first.

Big box got questions two and three spot on, but not question 1. You get final attack Materia by winning at the battle arena in the gold saucer.

First buy Omnislash and W-summon from the the arena gift shop using bp (battle points), you get this by fighting in the battle arena . once you have omnislash and w-summon talk the man standing next to one of the gift shop machine and he will say something like " harder opponents? sounds like weapons if you ask me" thats your hint to fighting the 8 harder battles, now go out in the air ship and defeat ultimate weapon, he is located in mountain lake either near junon or nibelhiem which ever it is, fly around in the high wind and you will find it he, is a coward and runs away when ever he recieves enough damage.

Keep chasing him and eventually he will make a stand at cosmo canyon defeate him there and get cloud's 'Ultima weapon' his ultimate sword, now go back to the battle arena and get amass a further 64,000 bp you will then be given the chance to battle the 8 harder battles, when you win trade your points to recieve the final attack materia!
you can now make your team virtually invulnerable, Pair it up with Pheonix summon Materia and then try and master them both, if all your party die then the final attack will kick in, and summon pheonix which will revive your team (because pheonix have healing powers) and damage your opponent just make sure you have enough MP.

Phew!
Good luck, because it's not easy!

1.It is a Chocobo eacing gift.You have to do really well to get it.
2.You need to use them often.Try equiping them in triple growth weapons which are Cloud's apocalypse and Cid's trident.
3.You need to have learned both level 1,both level 2 and both level 3 limit breaks.Then you should be able to equip them.

1) Keep doing the battle arena in the gold saucer and you will eventually be asked if you want to do some special battles against some harder opponents, if you win this you can get the final attack materia.

2) You just have to have them equiped and battle monsters. You can level them up faster by equiping them on weapons and armour with double or preferably triple effects. Make sure its not on something with the nothing effect.

3) You need to have learnt all of the level 1, 2 and 3 limit breaks first, then you should be able to give those characters there level 4 limits, which may I add are very cool, especially omnislash!