You know ANet might not have planned the NF tie-ins with Prophecies and Factions, therefore the Mursaat may have no tie-in.
A) ANet plans the NF story ahead of time, they do the Corrupted Tombs, Margonite references in the Crystal Desert, and Mursaat as forerunners to the grand scheme revolving around Abaddon.
2) ANet did not plan NF until they made NF. They say "oh let's reference the older games since people love that!" and then work with the story as though it were Play-Doh and make it so NF references Prophecies.