It should be interesting to see if Nalani was spotted in any of the videos along the route. I think that's why LE is asking the businesses and residents to come forward with any videos they have of Nancy driving by. They already know that Nalani is deceased and have found her. I noticed, like
@PommyMommy did, that they have stopped asking about the car seat, but just want videos and are asking for anyone that knew Nancy to come forward.
So, I am definitely thinking the same way that you are- that it is possible that poor Nalani was already deceased and left at the park, possibly the car seat as well, if there ever was one.