At madam puddifoot's, have harry focus on the girl inside to reach the slytherin hogwarts
crest.
In the yard where you found neville's shovel, use the apparition point to get into the
next yard over. Use the gun-chair there to blast six pictures of death eaters and unlock
the ravenclaw hogwarts crest
Use reducto to unlock the cellar door, left of the bar. In the cellar, grab a pair of
spectrespecs, pull open the barrel in the bottom right corner, and assemble to spectre
pieces to make a pump that will clear the water from the floor. Now you can use the
weasley box on the left and launch a rocket that will unlock the hufflepuff hogwarts
crest.
Send a pet up the pipe in the upper left corner to knock down some jars and get the boiler
going, then assemble the distillery and set both dials to match the picture on the left to
brew up the gryffindor hogwarts crest.