Hi. Your project sounds very interesting. Psychological themes in games have always been interesting to me and I'd love to work with you.
I have a question, though. Do you have any preference about the art style (besides 2D anime)? While I do draw anime/manga style, I don't have any samples for gothic horror. I can always make something quick if you want.
Also, you said the pace of the development will be quite relaxed, so will there not be any hard deadlines? Because if that is the case, making 12 characters won't be a problem for me.
It's also okay that it won't be paid, but in that case, I'd love to use this project for my portfolio.
Other than that, I would also love to use this project to learn Spline 2D. It's a program that lets me animate static images. Much like what you'd see in Reverse 1999.
Here's my portfolio: https://www.artstation.com/vanessa_boll
I hope the artist role hasn't been filled yet and I'd love to hear from you.