Third Battle: After the cutscene you will go against the dragon by using a ship to destroy it. First you have to destroy the tail. Constantly shoot it with your lazer, and when the enemy ships fire at you, use the Drain button to gain energy from the attacks. When the gauge is completely filled, use the mega lazer by using triangle, which does a lot of damage. Repeat this system until the tail is destroyed, and when it is, the dragon will roar and send a bunch of missiles at you. Simply dodge them and continue on with the engines, and use the same system. When coming to the wings, some flying sacrifical bombing Nobodies may come and try to kill you by blowing up. Simply attack them with Riku's and Sora's Keyblades, or use lazer fire, which will knock them into the wings and cause damage. Once the dragon is grounded, you will come off the ship to face Soldier Xemnas again. Use the same strategy, except this battle is easier, because he does not use the Organization Weapons, just his sword and the energy shield. When you cause enough damage, the dragon will knock you back, and you have to glide back to Xemnas. Use square to glide, and find a floating building that is not coming at you. Use the triangle ability to knock it at the dragon, then triangle again to destroy its shield. Glide to the knight and continue to attack him. Use the same strategy until dead. More to come!
And yes also use Dark Aura to knock the soldier out for a second and make sure to equip the right abilities.