There are tons of non-Disney movie themes that play all over the place in the area around the Great Movie Ride as well. These are called "needle drops." They are commercially-available soundtrack recordings. Disney can play such things as a background loop with no financial obligation (beyond buying the recordings at retail).
Scott
You're right about the tracks being used.
But, they are not "needle drops," nor are they free to use.
Disney must adhere to music clearance agreements with the likes of ASCAP, BMI, SESAC, and maybe QRSTUV.
Needle drop production music is another category of music clearance, and is (for the most part) original music that (often) is specifically written to "sound like" certain well-known themes from films.
It can be purchased under several license agreements, such as "buy-out" (free to use as much as needed for the one-time fee) or true "needle drop,"
which is payment based on the number of times the track is actually used.
I've dealt with production music for decades, and it can get pretty complex.