4th Gen Pokemon Platinum Team Help

I am trying to beat the elite four but I have found it quite a challenge with my current team. Can someone please give me feedback on my team?

Empoleon - Level 56
Item - Splash Plate
Waterfall
Drill Peck
Ice Beam
Flash Cannon

Garchomp - Level 55
Item - Soft Sand
Strength
Dragon Rush
Earthquake
Surf

Staraptor - Level 52
Close Combat
Brave Bird
Fly
Steel Wing

Kadabra (will evolve soon) - Level 51
Item - Mind Plate
Psychic
Shock Wave
Reflect
Shadow Ball

Magmar (will evolve soon) - Level 50
Item - Magmarizer
Flamethrower
Brick Break
Rock Climb
Fire Punch

Weavile - Level 50
Item - NeverMeltIce
Payback
Rock Smash (advice for another move please?)
Focus Blast (probably need a new move, forgot about poor sp. attack, any advice?)
Avalanche

The match-ups I was considering was:
Aaron: Staraptor and Magmar, Garchomp's Earthquake for Drapion
Bertha: Empoleon and Garchomp, mainly Garchomp since Empoleon doesn't survive long
Flint: Empoleon and Garchomp
Lucian: Weavile and Kadabra's Shadow Ball
Cynthia -
Spiritomb - A strong STAB, probably Garchomp's Earthquake
Roserade - Magmar or Staraptor
Togekiss - Kadabra's Shock Wave, Empoleon's Ice Beam, or Weavile
Lucario - Magmar
Milotic - Kadabra's Shock Wave
Garchomp - Empoleon's Ice Beam or Weavile

Can I please have some feedback on my team?
Also, where could I train? I've been lacking good training spots besides Victory Road for my Empoleon.

In a shocking turn of events.....
I WIN!!!!

My Garchomp decided to be faster than all of Cynthia's Pokemon, wrecking havoc. Garchomp and Kadabra were the ONLY POKEMON I USED in the Cynthia battle!

My Garchomp is level 59 now..

Hey there! If you're looking for some friendly feedback on your in-game Pokemon team, then here is the best place to post them! Fourth Generation Gaming is a board that houses discussions based on aspects of DPPt and HGSS minus the trading and battling sides.

...Which means, I'll have to close this up. If you have any questions, big or small, feel free to ask, I'd be happy to lend you a hand!