I tried to read that notebook when it was posted on line. It was hard to make sense of a lot of it, but now after testimony more of it makes sense -- demented, twisted, and freaky.
I think he's clearly mentally ill, but at the same time he clearly knew full well what he was doing was wrong both legally and morally and wasn't delusional or hearing voices or anything like that. So Guilty, "1st degree", all the way, Guilty, "extreme indifference", all the way.
Where this will get hard, I think is in the penalty and mitigation phases, where his mental illness will play into the consideration of punishment. Myself I'd prefer LWOP: get him treatment, get him mentally healthy so he fully appreciates the horror of what he did, and lives with that.
Also, LWOP comes with fewer automatic appeals, and there's going to be a bunch of appeals.