Icebreed2006:

Ideally, a logline starts with the inciting incident that upsets the status quo of the protagonist’s life; it triggers a causal chain of action: “After ‘A’-event, ‘B’-protagonist must do ‘C’-action before or else ‘D’-stakes”.

I don’t see a chain of causal action in the current logline.

What’s the inciting incident? The party? But the protagonist is a ‘carefree’, live-today-die-tomorrow guy. So it seems that throwing a party would be his s.o.p. which is to say, the status quo. So how can the party be the inciting incident?

If he’s throwing a party in response to the zombie outbreak — then wouldn’t the zombie outbreak is the inciting incident, the trigger event? And if it is, I think the logline would be more effective (and clear) if it were crafted to directly say so. It would state up front (not at the rear of the logline) what the inciting incident/trigger event is, and what it forces him to, like, as you said, “adapt, fight, and learn to survive in this new world.”

Icebreed2006:

Here’s the stumbling block in my mind with all your versions of this story:

If he and his friends know that zombies are loose upon the land, I cannot suspend disbelief that their first instinct is to throw a party. No matter how ‘carefree’ he is, the first instinct is to survive, to fight, to flee — not to party. That just doesn’t compute in my psychological calculus.

Now if he and his friends start to party not knowing there is a zombie outbreak — well, that’s a different story. But I can’t tell that from reading any version of the story you’ve posted so far whether that is the case. Please clarify.