I havent played a Pox list without Typhus. He helps get the ball rolling with his natural +1 Str, T, that only gets better with Vitality.
I would say a Tallyman should be auto include, just for the rerolls, and the heavy CP investment.
Ive been lucky thus far and my Pox Walkers survive Turn 1, but Ive been preparing for my opponents to wise up so now I try to bring 2 units, plus lots of fire magnets. Bloat Drones, Vehicles, Princes, even a Helbrute.