Lovely team, just a few problems.
Your team does need SR up, but I think more importantly that it needs to take out Machamp leads that can threaten your team late-game as well as KO irritating sleep leads, and possibly preventing others from getting rocks up. A great lead for this role is LO Azelf:
Azelf @ Life Orb
6 HP / 252 Atk / 252 Spe
Jolly Nature
-Zen Headbutt
-Explosion
-U-turn/Stealth Rock
-Taunt
This destroys Roserade, Breloom, Machamp, etc. and prevents bulky, slower leads like Swampert and Hippowdon from getting down rocks, which is important for your team. You could include U-turn for scouting purposes over Stealth Rock, though I think you'll find Stealth Rock is the superior choice. You could also use a specially-based variant, with Psychic, etc., but I think Azelf's powerful Explosion is too useful to eliminate things that you won't be able to counter immediately, and some Machamp are EV'd to survive even LO Psychic (pessimistic, but it could mess you up).
I'm not so sure about Curselax's functionality in the current metagame: without Sleep Talk, Infernape and Lucario easily crush you with Close Combat. I know your goal is to have them eliminated before you reveal Snorlax, but in my experience Lucario is usually left as a late game sweeper, and you could always be surprised by a random fighting type. I think a better idea would be to use a Pokemon that'll lure out your opponent's Fighting type, and an excellent example of such a Pokemon is Blissey (an offensive team MUST reveal its Fighting-type to take out Blissey, while Stall will usually rely on Toxic).
I also think that Flygon is not a reliable way to revenge kill, as it's annihilated by +2 Extremespeed from SD Lucario, which is the single most dangerous Pokemon for this team to handle. Therefore, you should consider Scarf Rotom, who'll serve as another pivot for Fighting-type attacks as well as revenge kill Lucario.
Infernape should be taken out by Azelf, no problem, except for Sashed/Scarfed variants, the latter of which is highly uncommon and can be handled, with prediction, by Rotom/Heatran, and the former of which can be hit to its Sash and revenge killed by Rotom.
Heracross is murdered by Heatran, no problem.
You also need a way to get rid of Steel-types, like Scizor and Skarmory, so I'd recommend eliminating Celebi, since Azelf does its job, and put in LO Substitute + Magnet Rise Magnezone, who'll help you take out any unscarfed Steels bar Scizor not locked into Superpower.
Ghosts will be handled by Rotom; if you want, however, you could replace Gyarados with Tyranitar, which would give you a good way to lure out Fighting-types as well as Pursuit-trap Ghosts.
With Ghosts, Fighting-types, and Steels out of the way, you don't really have anything to stop Snorlax's sweep. I think this means that you should leave out Fire Punch on Snorlax and instead include a better coverage move, like Earthquake.
