Version 1.2 of this mission is now available (Google Drive link in OP is updated) with the following fixes/changes:
- Statue heads are no longer frobbable and are now instead directly controlled by switches. This eliminates all bugs related to the statue head puzzle.
- If for some reason the statue head puzzle still fails, there is an alternative entrance added to the Restricted Library - a very concealed switch in the Chapter House will open the floor panel from that side.