Animals win easily through a combination of starvation and destruction of infrastructure. Farmland and infrastructure is laughably insecure against such a theoretical invasion. Even fortified pockets will eventually be over run as simple things like ammunition will eventually be depleted and arms and armor wear out. Animals 10/10.
Some especially hardened areas might be able to be created, but nothing on the scale of the world. Probably looking at creating enough underground fortified territory for <5% of the world population. Humanity is basically done in a generation or two though, as animals will rapidly out breed humanity's ability to fend them off. Only real solution would be to cause a massive nuclear winter extinction event (which isn't allowed by prompt) and wait it out in the fortified areas, though that has a strong possibility of wiping out Humanity too. Animals 10/10 within a few generation, Humans technically scraping by maybe 7-8/10 with drastic action.
Not much different than 2. Even if we managed to kill, say, 50% of the animals in that year, the exponential nature of breeding means it won't set them back that far behind schedule while humanity is pinned down in the bunkers.
The one exception to this is your rule
unnatural bloodlust for humans only.
Depending on how exact you take it, humans in disguises could potentially fend off attack permanently, by essentially working outside in biohazard suits and living as if we were on Mars. I'm assuming that's outside the spirit of the question though.