very very very interesting work here. wow, the direction of this thread has changed significantly over the past few days.
Just piecing some thoughts together here, so bare with me: what if this Zenaida name has always been KC's alias of sorts. On the surface, it would seem very odd that and Irish / Italian girl would try to pass herself off under such a name, but...
1. perhaps this all started as a name on KC's fake ID (obtained through an ID dealer, found it on the ground, whatever) from back when she was underage. Earlier references on her myspace page definitely imply she was no rookie when she went out for her 21st bday binge-fest. The ID could have just been close enough to work - some skinny woman with short hair, big eyes, etc. Besides, ID's don't have to be good (please don't throw me under the bus for this one,

but...) my fake when I was in college looked
nothing like me, including skin tone, eye color etc. If you're young and female, you usually just have to show
something at the door.
2. KC just got very used to throwing out that name when confronted. (Again, sorry,

but...) a decade later I can still recite the vital stats of the name on my fake ID, DOB and astrological sign included.
3. This came in handy when KC got pulled over and didn't want the trouble. (
Here's where I'd love your help with details): was she afraid of the wrath of Cindy and George? Would this kill her driving record b/c of previous infractions? Did her greediness cause her to not want want to pay such a bill (paying for a puerto rico vacation or a new phone were higher priorites)? Was it just some game she was playing, 'trick the cop'?
For whatever reason, KC gave a fake name, which she later realized could still somehow be traced back to her (or else she would have just skipped out on it), and started to panic when she realized she had to pay this bill without getting caught for giving false info. Maybe this whole ticket incident would have given Annie a lot of problems if KC did not pay up. Not sure how the law works in that case, but might explain their falling out...
4. Now she needs info of a ZFG, and fast!! in come frantic internet searches, possible robbing of Brevard County ZFG's office, etc - anything to get some sort of valid Z-id. I'm still piecing Sawgrass into this, but have some thoughts on that as well.
In summary though, what if
all of this ZFG "stalking" was done because of the traffic incident?? What if this had nothing to do with a murder or a plan for a murder?
But, conveniently, a few months later when KC is finally confronted with doing the unspeakable (and IMO she never expected she'd face police, just at worse her mother), this is the story that slipped out. Because of her earlier research b/c of the ticket situation, she has a name, an apt, etc. What if this was really the basis of a completely separate cover up?
oh, the tangled webs we weave....