The game is part of the FNC at its thematic base, not necessarily its mythos anymore. As Tabata said (yeah, I know he says a lot of things, but this one has been fairly consistent for once) but as the games world was built around the mythos of the FNC, removing it entirely would have meant that the games identity would have been lost as well. He also stated that the original intention of the FNC was to create a mythos that each games creators could do their own interpretation of. While that has changed for obvious reasons, as he says, the terms are removed but new original lore is now there as well.
So, thematic design wise, it *is* still part of the FNC. Mythos wise, it is mostly new.