1.) That "search" is rumored and could be the result of a click-through and we don't know when it transpired.It was a leaked LE source from what I read.
2.) It is extremely plausible that he put an item in the car and did not see the child. ...AND it has been reported that he did state this fact in interviewDo you have a link for this?
3.) If it was planned, he would have been better off with the mother going to daycare and getting the child. That timing makes no difference in this case.I disagree, he wanted /needed control over the "discovery" of Cooper.
4.) Where he pulled over and his state of mind and denial have no bearing on his guilt or innocence. It absolutely does, I believe it was reported, his behavior raised suspicion.
5.) I'm not sure where the smell of the car comes in. I have researched this case and am unaware of a smell issue.It was reported responders smelled a strong odor in vehicle
It is most plausible that this is simply another hot car incident.