Random Pokémon Challenge team

[Ninja Caterpie]

So I had to make a random Pokemon challenge team and, seeing as I'm on Emerald and doing the Battle Frontier with it (;-;), I'm going to need all the help I can get. Natures are horrible, so I won't even bother mentioning them. I can't believe I didn't try for good natures. ;-; I'm not going to bother breeding, so (most) Egg Moves are out of the question, except on Umbreon.

Anyway, in no particular order, here is my (to be) team. Believe it or not, I'm (probably) going to need Umbreon's healing abilities in order to beat the Elite Four if I don't grind at all.

Skarmory @ Leftovers
Ability - Sturdy
- Spikes
- Roar
- Aerial Ace
- Steel Wing

Umbreon @ Leftovers (?)
Ability - Synchronise
- Toxic
- Wish
- Protect
- Baton Pass

Flygon
Ability - Levitate
- Dragon Claw
- Earthquake
- Fire Blast
- Giga Drain

Sandslash
Ability - Sand Veil
- Body Slam/Return
- Earthquake
- Rock Slide
- Swords Dance

Tentacruel
Ability - Clear Body
- Ice Beam
- Surf/Hydro Pump (I'd rather go Surf, because the Battle Frontier is heavily haxy against me)
- Substitute
- Giga Drain

Machamp
Ability - Guts
- Bulk Up
- Cross Chop
- Rock Slide
- ???

Yes, a Special Flygon because my team lacks Special power. ;-;

Also, items. Help me or I'll be using 6 Leftovers, lol. There's no Expert Belt or Life Orb in Gen III, which is really annoying. Maybe some hax-items? ;-;