This is a pretty good Wifi team you've got here.
Firstly, get rid of Blissey for sure. This team is pretty mixed sweeper weak, so you'll need more "generic" walls in Diamond and Pearl, such as Vaporeon, Bronzong, etc. Standard HP Electric vaporeon should be good, Wish+Protect for recover and team support. It'll lessen the Infernape, and Gyarados problem, while still covering Heatran.
Skarmory looks good, pretty standard. However, consider a Shed Shell on it as an item, so Magnezone can't trap you. It's usually more useful than leftovers. You may want to consider Gliscor instead, as he can handle Heracross and SD Lucario much better than Skarmory can (both maim him with close combat) and he can set up Stealth Rock and Taunt stuff too. Also provides some Garchomp coverage. Weavile can always move in if it gets out of hand. Bronzong is also an option, as it covers Weavile and Deoxys-E but then SDluke and Heracross continue to be a problem.
Gengar looks OK, pretty standard. If you're set on Substitute, at least try the Mcgar set ( Sub, FPunch, Hypnosis, Shadow Ball-- 96 Atk / 174 Spa / 240 Spe, Hasty, Expert Belt) as it can really mess up the opponent. I find that it totally ruins offensive teams, and, if your substitute is intact after a kill, Weavile and Tyranitar can't kill you. If you like the regular Gengar better, try Hypnosis over Substitute and use Specs, Scarf, or Life Orb as an item.
Garchomp is standard, try Yache Berry; it makes it pretty much unstoppable. Swords Dance on the switch, kill their counter, and then try sweeping again later.
Infernape is good for this team, excellent wallbreaker... but again; you already have three good sweepers. To be honest, I would ditch him or Garchomp for Bronzong or Metagross if Weavile and Deoxys-E become problems.
EDIT: whoa buddy, you can only bump every 24 hours :P