As always GreyWarden, I appreciate your kind words :)
As for how many days, my original story was about 28 in-game days. Currently it is looking it will go a bit more than that. But, I have multiple endings planned with choices near the end so I'll be working on this project for quite a while and much could change over time. As for ascending the girls further (like Rin's Fury), only the 3 main Neko (that were written into the world by Karen originally) will have special abilities like that.