Hi,
yes, the examples compile on mobile, I tested it. basically you can have as many joysticks you want on screen, they will work as expected ( they rely under the hood with the Unity event systenm so you are safe).
I always try to make samples with the lowest Unity version so that everyone benefits from it, If I make it for u5, u4 users would not be able to use it, and it allows users to report any issues with new releases, and then I modify the content to work across the board.
Bye,
Jean