the only thing that makes sense to me is that adnan, jay, and jenn are all lying to protect themselves from....something. jay's ever-changing stories, adnan's selective amnesia, and none of the call records/pings lining up with any versions of the stories leads me to believe all three were involved more than they'd admit. i think the prosecution's timeline is wrong and based on selective information (such as the 2:36 phone call being the only one that fits part of jay's story). i think both jay and adnan's stories serve to protect jenn by eliminating her part (she may have only served as a confidant but i do think she knew what was going on).
high or not, there's no way adnan would forget everything about the day le called him to tell him his ex-girlfriend was missing. i thought yesterday about significant days in my life and i recalled a day three years ago when i was informed of the death of a loved one. i could tell you a pretty solid timeline of that day...three years ago....simply because it was significant. i don't buy that adnan can't remember anything about the day. i do think he's taking advantage of the well-meaning mistakes of others. the girl who said she saw him in the library, others who offer any version of "he couldn't do it".
i think jay wanted badly to be seen as a streetwise hustler. he mentioned to the cops that he had a "rap sheet" and they responded that he'd been arrested once for something minor. even then his response was about how many times he had been hassled by the cops, etc. i think adnan used this to get jay involved, but once the deal went down i think jay got REALLY scared about the potential for life in prison. his version of the story makes sense (lies and all) if you view it through the lense of him minimizing his involvement. even the parts of his story that change (where he was, where the body was, where they went) are variations of minimizing his involvement in the actual murder.
he knows where the car is, so we can say for sure he was involved. he cops to helping bury her body (a very serious charge), but why implicate himself in that when there wasn't any evidence? because he's ok with taking the rap for that if it means staying away from admitting that he was more involved in murdering her. if jay had done it himself (murder for hire, etc) then adnan's only job that day would have been to have an alibi, and he doesn't, so it says to me that jay was an accomplice not the main guy. since we know jay was involved (he knew the car location, admitted helping bury her) then who else could be the main guy but adnan?
the rest of the story's changing dialog i attribute to trying to cover for others (jenn, maybe more) who knew what was going on and could be in trouble.
all of this is just my 2 cents.