SubSalac Garchomp is probably the deadliest and best of the sweepers IF your stall team can take down Bronzong/Skarmory (use Wobbuffet/Magnezone)
Garchomp @ Salac Berry
Jolly, 252 Attack, 252 Speed, 4 whatever
Sand Veil
Substitute
Swords Dance
Outrage/Dragon Claw
Earthquake
Outrage >>> Dragon Claw
The best revenge killer would be Deoxys-E, outrunning even Scarfed pokemon with its speed. You could invest more speed to beat base 95+ Scarfers but it hinders your damage with Superpower.
Deoxys-E @ Life Orb
252 SpA
156 Attack / 96 Spe (outruns ScarfHera)
108 Attack / 148 Spe (outruns +nature base 95 Scarfers)
Naive/Hasty
Superpower
Thunderbolt
Ice Beam
Psychic/Psycho Boost
Once again, Psychic > Psycho Boost for your purposes.
It is worth mentioning that Bronzong beats both of them 1-1, Metagross, Jirachi, Swampert, basically anything that doesn't get hit super-effective will counter DeoE.
SubSalac Chomp only fears Bronzong and Skarm, but it will be weak without SD, same speed as ScarfChomp BTW.
Steel types are a major problem for Stall teams, basically have something for Meta, CMJirachi, Heatran and the like.
IMO, Regice and Articuno both suck at the task of a special wall, Flamethrower and Stealth Rock would be a major hindrance. Cress is Pursuit weak, so Heracross/Tyranitar would be free to exploit that weakness without Reflect and defensive EVs, and not to mention besides Twave Cress can't do anything to special attackers.
Blissey and Snorlax are the best choices. Zapdos could work but it is more offensively oriented. WishBlissey by far is the best variant as it can provide much needed support for your team, and can Protect to scout moves and heal with Wish.
A stall team needs a sweeper for lategame cleanup and a backup incase one of your pokemon get destroyed by a ChainChomp/mixed sweeper, or a critical hit happens.