Ok so Taunt prevents you from being taunted, and Toxic-spikes+Whirlwind spreads status but this last one works better with Stealth rock or Spikes as it continually does damage. The Pokemon are going to switch in anyway so remove Whirl-wind and swap for Earthquake to get rid of other poison and steel types.
You should keep haze because you never know when it might be needed. If you have will-o-wisp you can take some of those Defense EVs(Burn lowers attack by the way) and invest them in S.def maybe a 124 def and 124 S.def spread. When a fire type comes in just switch to Tentacruel.
Creative but is not the best use of Gengar he is not bulky enough to take major hits and cannot really work substitute without Hypnosis. If you want to run that set swap Disable for Hypnosis. Personally I prefer the Straight forward sweeper with Timid, 252 Speed and S.attack, 4 hp, Focus sash, Shadow-ball, Thunderbolt, HP(Fighting)/Focus-blast, and Giga-drain.
Go with Earthpower it is actually stronger than E-quake thanks to Sheer force and it lets you put full EVs into S.attack and Speed, and the remaining 6 into hp(only 4 matter though).
I would put some evs into Tentacruel's S.attack because if you dont you dont even have a 200 S.attack stat so that may not OHKO Swampert even with HP(Grass). Aside from that great set.
doesn't really work that well with this role. He can be a special sweeper: Nasty-plot, Air-slash, Heat-wave, Dark-pulse with focus-sash or Physical sweeper: Acrobatics, U-turn, Zen-headbutt, and Confuse ray with Flying gem.
As a whole this team is good personally, as my name suggests, I am more of a fan of fast and hard hitting methods as opposed to walling methods but this is good. But I would reccomend the Physical Crobat set because other wise Drapion is your only physical attacker. Also dont think that Blissey will be killed by Drain punch by Gengar I did the damage calculation and you can't even 3 KO her.