I know that making more zombies is most likely on your agenda for the future, but instead of modeling a bunch of zombies, you could make a system that randomly generates zombies. for example, you could have certain charecteristics that are limited, allowing for a realistic chomper to be created. This could be run server side so that all zombies look the same to others. But if this were added you would have to make something that allowed that sae zombie to spawn back if the player left its area, so that a different zombie doesnt spawn when the player returns. Ruining the emersion.