i had found the first and third scrap, couldnt find the 2nd, so i tried every remaining combo until i got it, which was probably a waste of time, but bottom line, i opened the minotaurs room and the back garden, but have no idea where to go after doing the bridge puzzle.
last scrap is probably in the library, its in one of the books on the top right you need the spade to dig up the gardener ghosts remains in the room following the bridge puzzle, which is in the bottom right of the first room inside the plantgirl area