D flat Major...

Having found a musical score for Defying Gravity from http://www.operalady.com/Vocal%20Sheet%20Music/Wicked_DefyingGravity.pdf I discovered that the key it is written in is D flat Major. 

From this, I decided that in order to create another three harmonies for my piece, I needed to first completely understand what the D flat Major scale is.

Now, since I understand what chords go into D flat Major, I decided to assign notes to each of the four parts (SATB). 

While I'm still not 100% sure on these notes, it is what I have decided on for now and may be subject to change as the project continues.