I'm no CK, but might I suggest Heatran / Gliscor / Dragonite / Tentacruel / Snorlax / Swampert / Vaporeon? Reasons:
An obvious possibility with his Flash Fire. He also has some pretty solid support moves, such as Stealth Rock, Will-O-Wisp, Toxic, Roar, etc., thus he makes an excellent staple to your team defensively. You could also opt for the more aggressive Heatran with Specs/Scarf, or even SubTran.
Taking in Heatran doesn't even hurt the team at all. You'll double up your weakness against ground attacks, but Tangrowth and Togekiss both resist and are immune to it respectively, while Lickylicky has a decent amount of defense to come in on EQ's, just not as well. Your water weakness grows only a bit, but the overall bulk of the team should manage Surfs/Hydro Pumps for the most part.
Gliscor is reasonably bulky, or for the most part physically sturdy. Now, he isn't exactly resistant to fire types, but his typing makes him more of a threat depending on whether or not your going to get 2HKO'd or not. He can counter fighting hits quite well, which means you wall in those Heracross who otherwise may haunt this team like a living nightmare. He get's Roost, so the reliable healing certainly isn't a bad thing.
Dragonite, more focused on LightScreen variations, can also be very useful. He's already resistant to fire, immune to Earthquake, thus an ideal pair for Scizor covering each others weaknesses. He has a plethora of support moves, such as the already mentioned Light Screen, Thunder Wave, Toxic, has a reliable healing move, and so friggin' bulky. 91/95/100 defenses and a monstrous attack stat, he can help a lot.
However, the drawback is you open up your Ice Weaknesses a lot. More specifically, your lack of a reliable defense against something like a Specs/Scarf Ice Beamer crippling the team. You already have two resistant (I'm pretty sure Mamoswine is resistant, although he might take neutral damage), but as said you'll become tremendously weak against Ice Beamers in particular. Light Screen Dragonite can relieve this, but for only such a long time.
Thick Fat obviously gets the job done. Curselax/ReSTalk certainly are the better options, as going with a more physically oriented Snorlax may just slow down the team. You'll have an extremely solid Ice/Fire resistance, and you'll just shut down Starmies and Heatrans.
Using Snorlax however will open up that unnecessary fighting weakness. Although Togekiss and Tangrowth take care of that quite nice, the thought that your physical powerhouses can be taken down by abusive Close Combats (By ScarfChan perhaps? ) may not be a great choice. Although he is a great wall, more Pokemon with Trick will make Snorlax a living nightmare, which shouldn't be a problem for now, or at least until Platinum is released in America that is.
Tentacruel / Swampert / Vaporeon
Tentacruel gives you some nice support, stopping the random Toxic Spikes, as well as being able to provide some for your own. He's just an amazing sponge with his huge Sp. Def, and I can vouch from personal experience of using him. He takes Thunderbolts like a champion with the right EV spread. Couple this in with being resistant to fire/ice, and he can really cover up that part of the team. Knock Off is a nice help as well for catching a few Poke's off guard that rely heavy on their item obviously.
Swampert gives you that nice satisfactory wall, providing your phasing needs which you lack, gives you Stealth Rock, and can manage on his own. He lacks a reliable recovery move, but may not need it too much if you use him right. He can cover Togekiss decently well soaking in the Ice hits, as well as Thunderbolts aimed at Togekiss. With his bulk, he's also quite solid physically as well.
Vaporeon will also cover your phasing needs, as well as Wish support which your team certainly won't mind at all for the immediate healing.
Starting with Tentacruel, you'll reopen that slight ground and electric weaknesses, however your team should still manage to do well with it's resistors. Swampert will make you more weak to Leaf Storms by Roserades and Venasaurs, as well as the random Grass Knots carried. This weakness isn't that bad, as it's only shared with Mamoswine. May want to watch out a bit with Grass Knots however. Lastly, Vaporeon will expose a slight Electric/Grass weakness, but still perfectly manageable with the team you have.
If you ask me, experiment a bit. On paper, my last three recommendations as well as my first one sound more ideal. If your more crazy however, the others may work. Really depends.
Oh look, beat by CK. Anyways, my point still stands, and that's of course basing it off of replacing Gallade.