Here are my thoughts:
Poison Heal Goodra: Getting kind of sick of seeing Poison Heal theorymons, but I digress... Anyways, this fits very well flavor-wise, and it certainly does fix her main flaw in lacking recovery. Anything you can say for anyone with Poison Heal applies to Poison Heal Goodra, and her other abilities were kinda meh. Gooey is good in theory, but I never saw anyone dramatically effected by it. Her bulk, as we all know, is excellent, tanking special attackers very well, and Poison Heal will certainly make her role easier. Normally, I'd vote for her, but I really would like to take a break from Poison Heal theorymons.
Magic Guard Froslass: This sounds like a decent idea. A Ghost-type with Magic Guard always sounded like a good idea to me, though I would have preferred this on Dusknoir or even Spiritomb, just something more defensive. But that aside, Froslass becomes an excellent revenge killer, capable of jumping in on anything and revenge killing with excellent coverage with Ice Beam, Shadow Ball, and Thunderbolt, and Destiny Bond becomes much easier to pull off, since you don't have to worry about field hazards anymore.
Poison/Electric Weezing: Say hello to theorymon's defensive Eelektross. We desperately needed a complete counter to Mega Pinsir, and another Talonflame counter never hurts either. Defensively, he's gains great resistances to Electric, Steel, and Flying, while Levitate prevents him from bearing a 4x Ground weakness, all at the small cost of a singular weakness to Psychic. Not bad at all, to say the least. He already has semi-recovery in Pain Split, a status move in Will-O-Wisp, and now it makes sense that he has Thunderbolt which he can hammer Flying-types with, and 85 special attack is pretty good for a defensive Pokemon.
Dry Skin Escavalier: This is an interesting idea, and one that can go the extra mile. Dry Skin lets Escavalier check/counter most of the Water/types in OU, including Azumarill, Keldeo, Mega Gyarados, and Manaphy. He's already 4x weak to Fire, so magnifying that weakness doesn't even matter at this point. he can set up Swords Dance to punish Water-types for staying in, and has a free turn to set up if they switch anyways. Though his coverage is still meh, and his speed is still horrible.
All in all, my vote will go to Poison/Electric Weezing, since his defensive abilities are simply extraordinary.