Spiritomb would be a good combination with 'gross's Explode. 'Twould be cool to use.
Blissey's a good cleric, but will be raped by any Physical attack (and as you seem to be relying a lot on attacks that cause damage to multiple opponents such as EQ and Explosion, that wouldn't be a terrific idea)
If you want to look for a baton passer, I reccomend Celebi. Swords Dance/Agility Pass, use of Leech Seed, not a bad choice. Especially if you wipe out its counters early on.
Criticism for the two leads - I would prefer Waterfall over Surf on that Swampert. Purely because of another Physical attack. But from what I understand Swampert is generally used as a mixed pokemon, so it's prlly not the worse choice. But as for playing it with a Charizard, you may want Waterfall after all. That way you could replace Fly on Charizard with a more useful move (Rock Slide would be a good choice to catch Flying types off guard [removing counters for Celebi], although another special attack would be preferable).
Metagross with Choice Scarf is pwnage. Life Orb is okay, and as you plan on using him as a Revenge killer, it's prlly the better choice (especially for a double battle), but I thought I'd just put the Scarf suggestion out there (Meteor Mash the bitches!).
Flygon with Dig is obviously a way to use Surf and Explosion without harming your other pokemon. If you keep Surf and don't use Spiritomb, this is a good option. Otherwise, I'd nerf Dig for EQ
Hmmm... and now I realise that Kingdra would have Surf (go Surf over Hydro, it hits much more often which is nice :]), so Dig remains a viable option for Flygon (and possibly Fly for Charizard). Ice Beam and Dragon Pulse are the other ones I'd choose (Draco Meteor = Special Attack Down = Bad for Special Sweeper). That is unless, of course, you use White Herb. But why settle for White Herb? The only reason you want it is to stop Draco Meteor from reducing your stats. But if you go with Life Orb, you will get enough of a bonus to cover that difference, on top of which your other attacks will benefit as well :3
Spiritomb would be cool, or Blissey. I use a Shuckle in the OU, that could be a good option, but I don't think I'd reccomend that for your team. And while Blissey would handle the Surfs very well, the Earthquakes and Explosions are nasty for it. Spiritomb, on the other hand, is great for the Explosions (not effecting it ftw =D), but it won't be as good with Surf as Blissey is. However, you won't have to maneuvre off the field using Dig or Fly when you plan on using Explosion, so that's a positive :3
So I'd prlly go with Spiritomb. Or Dusknoir. Dusknoir's more defensive (but less type coverage).
