As far as the scent thing goes, I'd say that the reason the innards work in Guts is to let the zombies think that Rick and Glen are zombies, not to mask their own scent.  In other words, it's not as though zombies have a heightened sense of smell; it's that the smell of dead flesh makes them not want to eat…

I believe they refer to it as 'the fights'.

Great article, Tasha - I've had this discussion about quite a few movies, and why they didn't work, whether in genre fair or not.