One that I'm quite fond of is when Simba and Nala head to the waterhold with Zazu. When Zazu flies down to tell them of the perceived blossoming romance, a few lines of "Can You Feel The Love Tonight" can be heard in the background on what I assume to be a flute.
I never noticed that before until I heard the extended score!
My other favorite is when Nala and Simba find each other again. You briefly hear a different version of "Busa" which is my favorite!
Am I just kinda slow in hearing these just now?

Anyone else have a favorite "hidden" song?