A: For those with more music training or tech savviness, I recommend using Apple's GarageBand. For anyone who's not quite ready to create a song from scratch, I recommend trying a program called Incredibox
($3.99; available for iOS and Android devices). This app is a music remixing and arranging tool. Users are able to create songs by dragging and dropping icons that represent different sounds (beats, effects, melodies and voices) onto a track, and layer the multiple musical loops on top of each other. It's so intuitive that your students will be making music in less than a minute and having a whole lot of fun doing it. Users are also able to switch styles of music within the app as they choose.
You could also try Music
Maker and Auxy, which are similar apps that offer large libraries of samples, or Splice
Maker, a free web-based platform that allows you to make songs by choosing the instruments, rhythm and timing included.
If you want your students to take ownership of the music as well as the dance, having them create their own songs on their devices in class is a great start, but keep in mind that these digital apps tend to lean toward electronic music following a distinct 4/4 musical timing.