Get 10 or more wins in Survival Mode in Single Battle. To use a character's EX form, press left or right on the character select screen.
Images from gallery mode
Beat Story Mode using two characters from the same franchise to unlock the first three rows of images. To obtain the other images, beat Story Mode using the same method, but in their EX form.
Narrator system voices
Successfully complete All Battle mode to unlock that character's voice under the "System Voice" option at the "Sound Settings" menu.