Multijuke have a fine Kidmode to keep it simple, and only require minimum 4 buttons to operate (Up, Down, Enter and Back) buttons to use. You might add a 5'Th button to carry a find.
MultiJuke exists to Linux as well Windows..
But, Touchscreen or not, you should test jukebox software out first, since these software have very deficient styles and might require deficient design to fit it presently. Specific, if itsshould operate by kids.
Building a Jukebox should been pretty much the same basic things like Arcades, but just have deficient design. But depend, which type of cabinet, you want to use and size of it.
Otherwice I have not build a real jukebox my self, and use my arcade machine to that, so I cant heap where you should get started.