Sword Art Online: Lost Song Cheats - PlayStation 4

Walk Through Walls
While controlling a character a mace, dagger or dual wielding swords, go up to a wall or obstacle and repeatedly use the first square button attack. You will slowly inch forward and eventually get inside the wall or obstacle. You can walk around inside the wall and bypass some locked doors or scenes. While inside the wall you cannot attack enemies with attacks or magic and they cannot attack you, but you can still buff or heal allies.

Custom Character Creation
To unlock Custom Character Creation just complete the first Island. After beating Fafnir you will be able to create a customized character in the Cafe/Multiplayer room. Talk to the girl behind the counter to the Left of the door.

Unlock Characters
Black Lotus - Finish the Story Mode and speak to Strea as Kirito. Strea will start to glitch and you'll fight her as a level 1,000 enemy (I lost and still got her).
Lux - Complete the game and speak to an Undine in the plaza with leafa and silica in party. Go to the dungeon in the top right of the map on Nibelheim.
Rain - Complete the game and you will find her in the first island fight her and you must win.
Seven - Post game you can play a short storyline quest with her by visiting Agil's shop after completing subevents with Rain.
Sumeragi - Finish story mode. You can find him in Woglinde on a floating island standing next to a chest after Dueling Rain as Kirito. Talk to him.