Before talking about your final Pokémon, let me change a couple out of place moves.
Swampert: Why have Surf? You already have Waterfall and would do a lot better with something like Hammer Arm.
Umbreon: With his attack stat, Feint Attack is going to do pretty much nothing. Mean Look, however, would be better.
Dragonite: Thunder isn't really the best choice for him. You already have a Raichu as an Electric type, so swap Thunder with Outrage or something else.
Now for your final Pokémon. Keep in mind that this is just a suggestion, and you can pick whatever you want. But judging by your team, I suggest that you choose Scizor. Assuming that you're playing X and Y (which by the way you should have mentioned somewhere in your question) you need the Fairy resistance, and Scizor has only one weakness (Fire), dealt easily with by your Swampert, Dragonite, or Typhlosion. And if you can get a couple Swords Dances in, Scizor becomes a great Physical sweeper. Here's a set I would recommend running:
Scizor @ Scizorite (X and Y) or Life Orb (earlier)
EVs: 252 HP / 252 Atk / 4 SDef
- Bullet Punch - Priority, so doesn't need Speed; takes advantage of Technician
- X-Scissor - Powerful STAB attack
- Swords Dance - Doubles attack
- Aerial Ace - Takes advantage of Technician
Hope this helps!