I don't really see the merit of CS Heracross on this team. What does it revenge? Latios/Latias is handled by Garchomp on your team, and Heracross isn't particularly fast (Adamant nonwithstanding). If Darkrai was still in the metagame, I'd say it was a good choice. But Darkrai isn't, so that's that. If you really want Heracross, I'd suggest a Choice Band with Guts, to give you a solid status absorber. Also, I'd replace Earthquake with Sleep Talk, since EQ has redundant coverage with Close Combat. Sleep Talk is also really good with Guts. If for some reason you don't want Sleep Talk, Night Slash or Pursuit is a decent other option. A CB Guts-boosted Pursuit or Night Slash owns Jellicent and other Ghosts fairly easily. Also, Ninetails might try to switch in on a Megahorn, but with CB and Guts, that won't be happening too soon.
Now there's Jellicent. Jellicent is your sole Ice-resistance. Agains a Hail team, Kyurem can just throw down Blizzards until your team dies (Without reliable recovery, Ferrothorn dies too quickly). One Draco Meteor on a slightly weakened Jellicent will spell the end for you. I'd suggest a more Specially defensive set on Jellicent, and a more physically defensive set on Ferrothorn. That's really your call, since a Specially defensive Ferrothorn can probably stop Kyurem long enough for Excadrill to start a sweep. That said, I'm not really convinced Jellicent is the best choice for your team. Your team seems to be highly offensive, and since Jellicent doesn't really do anything other than pivot, there are better choices for it's position. On the Ghost side, Gengar is an excellent choice. He's a very dangerous and oft forgotten Pokemon in today's metagame. A SubSplit set would work very nicely. His Special sweeping skills also compliment your team's Physical strength. TrickScarf Gengar also isn't a bad idea (Imagine tricking a Scarf onto Gliscor or Blissey, for example). If you want bulk over a Ghost-type (Since SpinBlocking isn't all the necessary these days), Slowbro works very well. It resists Fighting, Psychic, Fire, Water and Ice, all of which are dangerous attack types. It also recovers simply by switching out, meaning you can switch in, do something, and switch out without having to worry about recovering. With Jellicent, though, you have to Recover every so often. Slowbro's movepool is also fairly diverse. You could run something like Boil Over/Fire Blast/Recover/Thunder Wave to great effectiveness. Slowking is the Specially-defensive option if you decide you want that. Either Pokemon deals with Gliscor fairly well. Other great Water-types include Gyarados, Gastrodon and Milotic.
On Tyrannitar, I'd suggest a lure set to deal with the problems you've been having against Physical walls. Running a Special-oriented set with maybe Substitute and Focus Punch is a great wall-breaking set. Ice Beam also helps deal with Gliscor, who seems to be a pretty nasty threat to your team's sweeping abilities (To be honest, it walls you easily, barring Rock Slide flinches and Stone Edge crits).
Other than that, you seem to have your threats covered fairly well. Reinuclus isn't too much of a problem with Heracross and X-Scissor on Excadrill. Bulky Dragonite also probably can't get past both Garchomp and Excadrill. So good luck.