Just played the demo. Really good start! The characters were all distinct and their conversations with each other and and different reactions to things were interesting. There's a lot of puzzle potential revolving around the four different main characters with their personalities and theme colors. Like I was wondering if the four "muse" notes would serve as hints for something later. on. One thing I really appreciated that a lot of RPG maker based horror games have trouble with is I was never lost about where to go next. Some games leave you hanging and you have to backtrack to every single area and inspect every single thing to figure out what you missed to proceed, which is incredibly tedious, but that never happened here.
Of course the game only just began when the demo ended, and I'm assuming the puzzles will get trickier as it continues and the game will get scarier.
Also, I know you mentioned not being sure if you would charge money or have it be a free game. You could do the "name your price" option, and basically do both. If the game stays at this quality, I'd gladly put down a few dollars for it.
Really looking forward to Chapter 1!