Firstly: Hyper Beam is not a good move for Zoroark; most moves that need to recharge are bad options. Also, Zoroark is frail, and Hyper Beam forces you to recharge, which means Zoroark has to stay in battle for a wasted turn.
For a forth move, I would go with U-Turn, and replace Hyper Beam with Nasty Plot. I would suggest Extrasensory, but that needs to be bred onto Zoroark. Since this is in-game, you can get away with only have 2 main attack moves.
Lastly, you don't need the U-Turn TM for Zoroark, just go to the move relearner at PWT, and U-Turn will be available for reteaching to Zoroark (since it learns the move automatically at the start).