Honestly, maybe not the easiest concept for Disney to pull off when more than a hundred of their films (a little over half) have a main character with one or both parents dead or missing. Even with just the ones on the box, Ariel's mom is dead, Max's mom is dead, Tiana's dad dies off-camera during the movie, and we all know what happens to Mufasa.
I'd just like to interject for a moment. What you're refering to as GNU, is in fact, GNU/Linux, or as I've recently taken to calling it, LINUX plus GNU. GNU is just one replacable suite of libraries ,not an operating system unto itself. It is but another free component of a fully functioning Linux system made useful by the vastly complicated hardware to software communication protocols. Shell utilities and "vital system components", are not enough to be called a full OS , as much as some 80s guys that created POSIX would like it to be.