[quote name='Ryuukishi']Yeah, I remember there being some talk about needing to import the Origins save into Awakening, and then the Awakening save into Golems, and finally into Witch Hunt, to get everything to register.
And come to think of it I don't remember seeing Nathaniel Howe in DA2 and I know he was supposed to be alive in one of my imports. Maybe mine did glitch after all. I don't remember for sure though whether Nathaniel appeared or not.[/QUOTE]I think that's how I did it with mine, as I was told the "correct' sequence for everything was DA: O, Awakening, then the DLCs in any order with Witch Hunt being last. I think it was either you or Ink.So.Well that mentioned it way back in the day of the "correct" order.
Nathanial Howe showing up in DA2 was nothing more than a footnote in regards to the gameplay in DA2, and I think there was a side quest related to it. Nothing earth-shattering, all told, though he does end up being an ally at the end of DA2 if everything works OK.
Here's all the particulars about it:
http://dragonage.wikia.com/wiki/Nathaniel_Howe
The bug you mentioned is discussed on the link to the DA2 quest, where it mentions that if he's not in your party when you end the game, it glitches.