You lost me on the time frame - 3 hours ? I could be wrong but AB says EB saw Zahra at 230 am, on the 9th, not sure I believe that to start with though as AB later can't even remember what day he saw Zahra. We do know the mattress was tossed 2 or 3 days prior. The cars, according to the warrant were not taken until 9:41 pm on the 10th - well over 24 hours after Zahra was reported missing.
One thing that does trip me up though, is the fact that the remains found at Dudley Shoals were buried. I can imagine EB driving about and throwing parts of Zahra here and there, I don't think she cared about the child at all. Buried remains, just my thoughts, buried remains indicate someone cared enough to bury the victim. Most murder victims are tossed away, no significant effort to bury the victims. A large portion of Zahra was buried, just my thought, the person who buried her cared enough about her to do that. JMO on it though.