The only one I want to comment on is 3. 3A is better. "Only" refers specifically to three days, and should come directly before it. To say that he "only has something" is wrong. He has a lot of things other than "three days to live". But since situations do not arise in which a person has only three days to live and nothing else, 3B means the same in practice.
(You might see the difference by changing "only" to "just")