We recently discussed what is missing to add support for Leap motion. In a nutshell, the bindings available with the v3.2 of Leap motion SDK would need to be re-generated and compiled for python 3.
This is discussed at length in this post: SlicerLeapMotionControl in Slicer 4.11.0
We welcome contributions and if you would like to help out, we are happy to provide guidance. To move forward, consider adding comments and questions in the post referenced above.