Hmmm
Would be better fight for them Signs Aliens to fight the Yonkers Zombies then.
Solanum Virus can't infect other creatures besides Humans but it's lethal to animals supposedly. If you treat Signs Aliens as animals then a bite for the purposes of the Versus debate could be considered non-infectious but still lethal. Otherwise Signs aliens should be able to bash the Zombies into oblivion eventually since they are clearly bigger, faster and stronger. You'd have to severely damage the brain of course but I'm sure they could figure that out sooner or later.
Or at least figure it out before the Zombies figure out the Signs aliens weakness to water.
But if the Zombies can lethally NOM on a Signs Aliens, it might be more even.