As far as covering threats go, you've got most of them covered, so props on that, though I think Offensive LO DD Dragonite and Chesto Rest Kingdra can give you some problems. Firstly, I think you can test Choice Scarf Flygon over Tyranitar, firstly it brings a Rock- type resist to the table, secondly, it provides an alternate method of handling Chesto Rest Kingdra, who is a threat to stall teams such as this one. Your method of handling it I'm assuming is with Celebi's Perish Song, or luring in Outrage for Skarmory to WW. With Flygon however, you have a way to KO Kingdra outright, without taking the long routes. You still handle the same threats Tyranitar does, but you stand a much better chance against the likes of DD Dragonite/Chesto Rest Kingdra. 252 Atk/4 Def/252 Spe with Jolly is ideal, and you can use U-turn/Earthquake/Outrage or Dragon Claw/Fire Blast or Draco Meteor or Thunder Punch. Gyarados is handled by Rotom-A reasonably well, and you can use Flygon for an opportunity to fry Forretress and Skarmory switch-ins who expect an Earthquake or Outrage. You can even use Draco Meteor to lure in things like Gliscor and Swampert, and hit them with Draco Meteor. Draco Meteor is also a good way to throw off Offensive teams, as it will do quite a number with hazards support. If you do use Fire Blast or Draco Meteor, change the nature to Naive or Hasty. Optional changes, I think you could combine Skarmory's and Tentacruel's roles and use a Spike stacking Forretress with 252 HP/4 Def/252 SDef with an Impish Nature and Payback/Spikes/Toxic Spikes/Rapid Spin. I feel like you really need something on this team that can abuse these hazards to the fullest. There are two options on going about this, the first one is the more offensive approach and utilizes a Sub CM Jirachi with 252 HP/4 Satk/252 Spe with a Timid nature and Substitute/Calm Mind/Psychic/Thunderbolt. This provides a great way to maintain your Lucario check, a way to address Water- types, and abuse the hazards to it's fullest potential. Swampert, Celebi, Tyranitar, and Hippowdon love to switch in on Jirachi. However, with Toxic Spikes support, all four are crippled to the point they're forced to switch out, or eat up accumulating poison damage. Basically, this Jirachi can destroy it's counters via the hazards provided by this team, and the reason I suggest it, is because this team provides the correct support for SubCM Jirachi. Additionally, you can try Wish+Calm Mind Jirachi for a more defensive approach, still maintaining the sweeping capabilities, in addition to being a supporter with Wish, for Heatran, Forretress, and Flygon. CM+Wish Jirachi is a huge pain for opposing Stall teams, even more so withe Toxic Spikes and Spikes support provided by the team. Against heavy Stall teams, these two hazards will help it greatly to wore down Swampert, Blissey, and Hippowdon. Choice Scarf Tyranitar can't switch in to safely revenge due to getting poisoned (and you can always take it on with Flygon). Whichever Jirachi you choose, it will greatly aid you against the likes of Special Attackers, and will definitely love the support it'd get from the hazards.
GL