Other uses for feather fall: You can get to the Risen Road near Karlach from the druid's grove. From the same grove area, you can get to Edowin and his party from an alternate route.
Enter the room with Zevlor. Look for the climbable area near the book/map part and climb to the wine cellar attic. Climb up the ladder and you find an area that is otherwise inaccessible. Facing the water:
On the left is a narrow strip of land with jumpable gaps that leads to the area with Edowin.
On the right is a climbable wall leading to a plateau that overlooks the Risen Road. Feather Fall gets you there.
