for the painted chest to appear you need to finish the painting in the school auditorium (where you find nanami first) needs a lot of the green bar
The manor basement paint is a just regular paint used in the manor
And for the 7 additional clue looped forest basement bookshelf the codes are at the bottom of page 11 the mushrooms are cryptid but easy to figure out
The painted wood + mushroom in the cauldron is for hair and eye coloring useful for the perfect Festival of Life (clue is in of the pages) need to look up at the school Library
I think 1 mushroom + 2 painted wood for eyes and 1 mushroom + 1 painted wood for hair
Not every mushroom have results
This coloring is for only for the dream version of the MC dont know if it can transfered to the real world