it depends what you need.
Zoroark is a sweeper. It has pityful defence but excellent SpAtk and Atk. it can also be used to avoid damage. A common statergy is to send it out as a Fight type. the opponent will use a Psychic move and will do no damage.
I would go for the obvious special sweeper.
•Night daze (or Dark Pulse for that extra sliver of reliability)
Set posted by Pokemaster. But you can give it any move depending on the situation.
Umbreon is a wall. Moves like toxic and wish make it hard to defeat combined with great defencive skills. I would give it this...
Umbreon (F) @ Life Orb
EVs: 252 HP / 4 Def / 252 SAtk
Modest Nature (+SAtk, -Atk)
•Hidden Power [Fighting]
hex's moveset which I often use. its attack is low but it can make up for it.
Choose them depending on what you need. hope I helped!