The quest seems interesting
There's two things I see that need fixing:
-You can set map difficulty in the map attributes (ctrl+M)
Then set the relative level of the mobs accordingly (Attributes > special > relative level)
If you don't remember the colours, have a look on tutorial island in the building that explains it
-The skeleton mages can cast spells but haven't got any.
In the editor open the 'Archetypes' panel. Select the 'forces' tab and pick 'ability' from the drop down menu. Add the ability you prefer to the inventory of the mob by clicking 'Add Inv'
You could also add a light (3 or so) to the small cauldron Sue is using and the fireplace in her room.
Maybe a light-source of 2 on the stairs, up to you.
When adding lights, don't forget to set Darkness in the map attributes (ctrl+M).
Looking forward to see more of the catacombs ~Kiana~