So I just reached the point where Josua talks to me at the waterfall and tells me that he thinks there should be war, not peace. After that conversation I wanted to go sell some stuff to Daniel but he is nowhere to be found o.O I even waited at his bed at night but he never turned up. Joshua is gone from his cave aswell.

This is what truly kills the DLC I believe: after completing it, everyone stops spawning in the map, and every character and NPC in the map will disappear. Ruins it for me.

Daniel went somewhere quiet to cry.

Seriously though, he should be somewhere in the Sorrows camp up until the finale. I'm pretty sure you gotta talk to one or both of them to start the final quest.