With regard to this phone call from the school and Terri giving Desiree an account of the morning:
If Kaine was already gone home when Desiree called Terri, then it's reasonable to assume that Terri and Kaine were otherwise occupied with LE leading up to the point that Desiree was called.
It's also interesting that Desiree called Terri, not Kaine, immediately. Also interesting that Terri was supposed to drive Kyron to Eugene to meet Desiree. For a woman no one trusted, Terri was sure trusted to help Kyron with his school projects, drive Kyron around, be the primary caretaker of Kyron, and drive Kyron when it was his scheduled weekend with his biological mother.
Having said that, if you left your child or someone else's child at school, and you were attempting to explain the events leading up to him being missing, what would you say? Wouldn't you say something like, "I left Tommy right here! I told him to tuck in his shirt and I waved and everything was fine and I left him right here!" What should she have said? Nothing? I want a lawyer? I don't remember?
According to Desiree, Terri giving an account of that part of the morning is suspicous, but according to Desiree, Terri not giving a full account of the rest of the day is suspicious, too.
This case is maddening.