Since the Third has the best stamina and defense here, it's Orochimaru's burden to make sure that he gets done with the Third - the pressure is on him. He's lucky that he has several techniques to prolong/save his life in battle, as that will help him here. Something that Orochimaru has going for him is the fact that we've seen him use Futons before on panel, which are the Third's weakness. Since that's the case, he might have something strong enough in his arsenal to dispel the Lightning clad armor.
If he doesn't however, his next best bet is to use his White Snake form and stun him with toxic gas. He regenerates in that form, so there's the chance that he can pull himself back together. It's still a risky move, and it shouldn't be too IC to begin with, so it's a last resort sort of thing. Once he's down, that should give him what he needs to land a 5 elemental seal on him.
If the Raikage can stop both of these, then I'll give it to him unless I can remember other things that Oro might have.