I haven't formed an opinion on this case as of yet but I wanted to respectfully play devil's advocate to your post.
If this RUMOR is true and two teachers saw Kyron leave with his step-mom, here is one possible explanation as to why LE still handled it as a normal missing child's case and conducted all the searches.
Possible scenario:
Step-mom reports him missing, then Le talks to the school employees. Two teachers tell LE they saw Kyron leaving with his step-mom. LE tells step-mom this and she says well they must have been mistaken and thought I was leaving with him but when they saw us together we weren't leaving.
Take into consideration we don't know where the teachers were have rumored to see step-mom and Kyron at when they assumed they were leaving. If they saw them outside in the parking lot that makes it more plausible that they left together. However, if the 2 teachers saw them in the school and assumed they were leaving, that's not as plausible.
If LE has no proof one way or the other that he left with his step-mom and she is saying they didn't leave together, well then LE would still need to handle this case as any other missing child's case and conduct searches, etc...