When it comes to release dates for the actual game (not betas), Gabe has always said "episode [X] by [Y quarter of year Z]" and usually makes it. 2016 was the target for episode 1, e.g, not the whole game. The problem comes when they overstuff the game with irrelevant shit no one cares about, and then say "Oh and also the remaining story is too big for just one more episode so we're going to go to four." And then they add more women who will almost certainly have four full CG scenes with anyone or anything but the MC, while the MC still doesn't have a consensual scene with Beatrix. (I know it's an H-game but she's so drunk she doesn't recognize you; that doesn't count.)
Classic case of feature creep. They clearly didn't learn their lesson from 1 and 2, where they did it right and added the fun side bits in the Gold Editions that came out after the initial full releases.
Anyway, to recruit Naz'Raala, first remove someone from your party. Then when she's in your room, talk to her with the Conversate option and you'll offer her a chance to join up. She'll agree. Exit your chambers, and she'll be standing right outside the entryway, whereupon you can invite her to join the party. (I don't know if removing from your party first is necessary but she didn't show up outside my door until I did.) She starts at level 40 which I guess might be useful if you're doing a fresh playthrough and don't have everyone maxed out already.