I'm sorry, but neither Lolorito nor TelAdel gain anything from lying to Merlwyb and Kan-E about Nanamo's death. Whichever of them came out on top, it would have been more to his benefit to have them believe that Nanamo is still alive, much like he has convinced the Sultansworn. Since Nanamo never actually managed to dissolve the Sultanate, she remains the most powerful symbol of power in Ul'dah, even though she lacks (lacked) actual power and influence. With that great show he put on for them, there is no doubt in either of their minds that she really is dead, and thus no way her name can be used advantageously in dealings with Limsa or Gridania.

Lolorito probably wanted Nanamo to survive for that very reason, hence his disdain at how "well" the plan has gone off.