For inf v inf, it would just have red outlined zombies, drones scattered everywhere, and red outlined mutated in some bits. It would play play out the same start as a survivor attack, just spawn drones and mutate. Your zombies will be blue outlined. It would be interesting to see how zombies versus zombies would go. Aoe would be required no doubt, drones.
Survivors would have just pads and deploy, then start the attack. There would be clumps of the bandits or raiders, some being clones of survivor units. Some would be excluded, like the water and oil FatMen, because what apocalyptic bandit would spray slushies on their enemies? The same would go for outlines of enemy versus you outlines.
but the researcher and biohazard for both modes. It will have to be blue is good for your guys and bad for them, and red is good for them and bad for you. Biohazards (excluding perks) would just damage characters without the same outline as their field.
Researchers would have to be tinkered in proletariats own way.
Basically, just the inf or surv, fighting the same units. Bandits and rogue packs.