*Spoilers* Jin and Mugen's Fate
Ok, so I might be alone on this one, but I was under the impression that Mugen, Jin and the old man who was helping Fuu's dad died.
Mugen was right beside a massive explosion. Right before Jin delivered his final blow, there was a flashback explaining that if he was faced with a more skilled opponent, he could sacrifice himself to reveal an opening. Sooo he sacrificed himself to kill the assassin.
The assassin said that those associated with and family members would be killed. Why would he make an exception for some old guy who meant nothing?
To me, and again I realize I might have really missed the mark here, the scene where they all go their separate ways, Mugen and Jin were both standing under signs. While those signs probably have locations on them, they were also crosses. To me that symbolized that they were both dead, and that their conversation was Fuu's way of saying goodbye.