Talk to any writer and you'll learn they have notebooks and apps filled with story ideas, character inspirations, lines of dialogue, etc. I think that's what that paper was: a brain dump of ideas. People keep speculating it was a coded message but that doesn't make sense to me at all. Why encode a document like that? For what purpose? I could see him writing in code if he was going to send that to someone but that wasn't the case. And, if it was code, why hide it? It took them months to find it so it's not like he had a line in his will telling his wife where to look.
I think there's a ton of stuff being attributed to his death that have nothing to do with it, namely the missing money clip, the disconnected cameras, etc. I don't think either had anything to do with Rey's death. That said, I absolutely think he was lured to that garage, beaten and murdered. That hole was the result of a straight drop at a high velocity. The jumping theory has been debunked for the most part. I think he was dropped from a helicopter (his friend had access to one) and his phone, glasses and flip-flops were dumped on the roof.
His poor wife. You can tell she's never recovered from the trauma. I hope she's not re-traumatized by having this episode air and having the internet start digging around her life.