I think the song "Hellfire" from The Hunchback of Notre Dame fits perfectly as a song for Parker and Lortsyal when they first started "seeing eachother."
The lyrics "I feel her, I see her, the sun caught in her raven hair is blazing me out of all control." Would be Parker's inner turmoil struggling with the fact that he's befriending a Na'vi, the very people he thinks so little of, this one woman is changing his mind through her gentle nature and shared interests (golf mainly lol).
As the song progresses and so does their "friendship", Parker struggles with the same thing that Frollo does, in a way. Parker cannot admit to himself that he is slowly having a change of heart for the Na'vi, it goes against everything he stands for, he can't let himself fall for her. He struggles a lot with fighting his feelings, much like Frollo, and blames Lortsyal herself for making him fall rather than looking inwards.
