and both were very peaceful, good deaths. So I don't think much of your options. But I picked "freeze" because that sounded by far the least painful of your choices.
I've been fascinated by death since I was a child, but seeing how peacefully my family members went has been an encouraging experience. They were 80 and 96, respectively. l think living a long, good life adds a huge element of peace to the end.
I'm noticing one option you didn't mention was thirst. And that interests me because essentially that's how my family members died. Both got to the point where they couldn't swallow, as a natural consequence of their respective diseases. Both of them said they had no pain, and the end came peacefully for both of them. My mom carried a water bottle with her most of her adult life. She never wanted to be without water. So that added a poignancy to her end.
As others have said in this thread, I hope your interest is academic at this point (are you writing a novel, maybe?) In 1992, when I was going through the throes of depression, I looked out in the back yard one Christmas Eve as the snow was falling, and I had an overwhelming urge to lie down in the snow and let it cover me up. But in the years to follow, I've been *so* glad I didn't do it.