Part 36: Side-Note: Post Floor 31, Wreath (post by Jegan).
If you leave the tower after that plot point instead of doing it all in one go, there's a special plot point with Nico where she talks to you a bit and is sad to see you weighed down all with this dramatic stuff. From then on, I'm pretty sure she'll always be the one to wake you up at home until you get to the ending.
Nope. There are some girls who won't show up (Cherrl for sure, probably Vivian) but not exclusively Nico. If you don't have any girlfriends at all, you'll get this.
Post 31 Part 1- Wreath