Well, what I would be curious to know is if Casey or the Anthony's had ever met, introduced themselves or befriended those individuals. This theory would seem more heavily plausible, at least in my mind, if there could be a "tangible" connection made between the parties and Casey/the Anthonys.
I mean, I lived in the same house from birth until my early teens and didn't know the names of all the neighbors, and most of them I only knew on a first name "say hi when you walk by and their outside watering the lawn" kindof way. KWIM?