Who would win? And the zombies come in waves of 146 at a time, and there's a 15 second delay between each wave. So if ninja aren't quick there could be a lotta zombies.
Well if the ninja had enough shuriken, and they were smart enough to aim for the head, and reuse ammo, i think one ninja could take out at least 200 zombies before his ultimate demise.
Zombies would go pretty slow, so all the ninjas would run places. Two ninjas would go and get crates of grenades, and the other would get a chopper, the other two would get in, they'd fly over head and just barrage the whole horde of zombies, at no cost to innocents since they'd already have been killed by the zombies.
Zombies regenerate, and the more innocents you kill, the more zombies are ressurected. And for every killed ninja, there's a zinjie (zombie-ninja). And those are gonna be hard to deal with.
Zombies don't regenerate when you blow them up. The only way to kill something that constantly regenerates is to take out its brain, zombies and all. Crates of grenades exploding would clearly do just that, as well as ripping them apart.