If Zoroark were in SSB4, this was my idea for the Illusion Ability:
It's a Special Move that allows you to transform into another random character on the roster (or maybe in that specific battle). While transformed, you gain the look, stats (speed, power, jump, etc.), and normal moves of the character you're copying, however, Zoroark retains it's own Special Moves and Final Smash.
So if, for instance, Zoroark's Side B was, like, Night Slash or something, and she was copying Mario, she would look and fight like Mario, but still use Night Slash as her Side B.