Question: How do the Heal skill and the spell Remove Disease (and related spells) function here? Does a Heal check stop the bleeding from a wound and delay activation of the T-Virus (or whichever name you're using in this world)? Does Remove Disease instantly cure someone of Zombification? What happens if you Remove Disease a zombie who's lost a limb? Do they regain life and start bleeding profusely? Just some things to consider.

Personally, I would only have Remove Disease apply to people who have just been infected (and thus, not died from the virus/probably haven't lost any appendages due to being dead), and have Heal prevent the activation of the disease for a number of rounds = to the number the DC was beaten by (probably like DC20 or so?). Delay Poison should function the same way it always has.

And please, don't take this as me trying to...I dunno, attack your campaign or anything. These are just practical problems that occurred to me as I was thinking about your campaign.