And maybe LE has asked all those questions and has the answers, but have not released that info to the public. Key to your post 'We just don't know'. jmo
But, you will note, MR made a point to mention that Dylan was up late prior to flying out, but the morning Dylan went missing was two mornings later, not one. Why bring up what went on before Dylan arrived (i.e. when Dylan was in Elaine's care) unless MR was directly linking Dylan's fatigue to his son going to bed early/crashing on the couch, etc? Instead MR uses Dylan's late night from two nights prior to explain why Dylan didn't rise the morning that Dylan went missing---two mornings later, not one.
Even if MR's responses are specifically in response to media questions, there is a skip in time...why mention Dylan staying up late two nights prior instead of what traspired the night before the reported disappearance? I find it notable that MR did not indicate whether Dylan went to bed early and/or stayed up late that night, but instead, makes a point to mention Dylan staying up late prior to his arrival