I believe it's tied to the ides of the restless dead.
The spirit should move on after death, but some spirits get stuck between worlds. Often it's related to the circumstances of their death. Maybe they had unfinished business, they died a particularly grousom death, or they were denied a proper burrial.
This is the normal way to begin a jury trial.
He's not admitting guilt, requiring the prosecutor to prove (beyond a reasonable doubt) to a jury that he's guilty of the charges.
If I understand correctly, NY has chosen to charge Murder 1 with a terrorism enhancement, which requires the state to prove claims about his mental state, intent, and motivation.
I assume that the defense is hoping to push for some sort of settlement latter in the pre-trial process, and/or to cast sufficient doubt over the specific elements of the charges brought