So... I have 8/9 outfits. I can't figure out what the hint "A mysterious intermediate material that cannot be used... Something might come as a surprise." means... if anyone has any idea on what this might mean, I'd like to know.
So... The materials for the outfits are:
Twig, hemp, cotton, wool, cushion chair, slime heart, fish and chips, thin book
If anyone has any ideas on the last outfit, I'd like to know... I've been searching for hours and out of desperation, I'm about to craft everything at least once.
For the facility, you have to talk to the bunny girl a few times. Try talking to her in different days, she'll tell you about the second floor eventually.
Update: I found one of the last 2 outfit materials. I've already updated the list of materials.