I made a mod that automatically makes all installed Anthro Survivors species work as zombies: Furry Apocalypse. It's configurable! Works in multiplayer, and can create completely human-free zombie hordes (there are no humans by default).

The complementary Anthro Survivors Deceased Skins mod makes furry zombies look grimy and rotting. Zombie rotting visual progression is coming along! But it's not currently published. Zombies would get progressively more decayed as time goes on. This feature requires both these mods.