I think if you can get Swampert burned, Snorlax should have no problem with it. Then, were it to Rest everything off, I'd explode to take care of it. Swampert isn't going to come in on Gengar to take it 1v1 and Gengar doesn't want to stay in, Giga Drain and risk a OHKO due to Hydro Pump.
I'm pretty sure Fire Punch is for lead Metagross(es) and I always thought the spdef evs on Duggys were to take +1 Kou Hp Grasses, but the Blissey thing sounds more reasonable.
avatar: azunch by Pyr0
netbattle: falkner, tapedeck, taurus