tataru:
http://img3.wikia.nocookie.net/__cb2...ARR_Tataru.png
nanamo:
http://img1.wikia.nocookie.net/__cb2...mo_Ul_Namo.jpg
they have way too many difference for be the same.
other point, i sincerly doubt they will have put this into the trailer of heavenward for rick rolls us with:" no she wasn't dead". even if she was alive and i say if.... her part into the story is over. even if she come back, she will do nothing good to the story. she was about to put down the sultana and create a new system where she will had no power. even if she come back, she will have no power and will have no role into the story.
the best outcome i can see it's raubahn, becoming the new leader of Ul'dah after we free him.... even if i'm worried that he will fall into darkness after this, and believe me if he is freed, some lalafell will die.
Nanamo, even if i adore her, is sadly dead and will probably never come back. it give deepth to the story.... it make the danger of the darkness and the chaos more important. because even if we are the heros, we can't save everybody. we need to accept this, because, it's the sad reality. it will make our decision and action have more weight...
and i already see the time where Ul'dah learn the death of Nanamo... we risk to have one of the more sad CS with her funeral and the people crying her loose.
other point extremely important, it make the bad guys of Ul'dah more evi ,we all want to get our hand on them and punish them...