Two different conclusions by LE probably means acquittal.
If two different detectives look at the evidence and come to opposite conclusions, that's an acquittal.
I tend to agree. The state is going to highlight inconsistencies in Zimmerman's statements and, IMO, rely heavily on the professional opinion on LEO to make their case. Differences in LEO opinions will go along way toward doubt - especially if those opinions can be shown to evolve when the case came to the public attention. That's how I would try to cast it - the police were satisfied with Zimmerman's account until political pressure was exerted.l If O'Mara can show that in the timeline, I think he creates serious doubt.