http://media.nbcbayarea.com/documents/Arrest Warrant - Alexis Botello.pdf
First, it looks like she did show them where the body was on the 6th and they were able to get a copy of the Walmart video. Look at the time for when they were in the Walmart store though! 8:39 pm! That is hours after her description of when the baby died. They obviously didn't impulsively run to hide the baby's body. They had all day to plot and plan.
Secondly, in that report it says that there is bedding at the house with vomit on it. If the baby was on the floor vomiting green stuff, why would it be on the bedding and not on the floor? Did they put the baby onto the bed to attempt CPR vs attempting it on the floor?