How do I satisfy all these ghosts

Hint 1 of 6:

Did you find the shovel?

Hint 2 of 6:

It is in the secret room west of the library.

Hint 3 of 6:

Each ghost left something it wants in its own grave.

Hint 4 of 6:

Read each tombstone until you find the proper match.

Hint 5 of 6:

Be careful, the shovel will eventually break if you dig in a wrong spot.

Hint 6 of 6:

The last ghost, a little boy, will lead you to the attic.