Instead of having zombies be rescued, what if you could develop a sort of hormonal CONTROL of zombies, and produce them as replacements for dogs?
Would be an interesting effect : you could do some very basic alterations to genetics, to get them to attack aliens or hostiles, using a "hive" mentality (working for a central host, being the commander) and in return, you have soldiers who dont feel pain dont have morale, and are extremely disposable, but at the cost of needing to feed in new humans to keep production up, as well as putting in new parasites. On top of that, maybe a small moral hit per zombie in the squad, because having one in the crew is creepy as all hell.
....Forgive me if this is already an idea, I've barely scratched the surface, and not even reached 1999, but the idea of feeding in captive humans of any type, and zombifying them with the xcom brand zombie parasite sounds very cool, particularly if you can use spare dead zombies to then create infector zombies, and then use infector zombies to convert hostages into other zombie.
It would be a pain to get done with all the ways to zombify (kinda like the rob / enslave section in piratez) But it would be a really cool effect, and really neat to throw an infector into a house of exalt crew.