My understanding from the Leap Motion team is that their new Mobile Android SDK is not complete and has taken a backstep to other projects (north star and others). If anyone has heard differently let me know we would love to leverage leap motion on the original Vive Focus as we wait on the Focus Plus.
According to an engineer at Leap motion back in July 2018,"Unfortunately, the Vive Focus is a mobile based headset so our current drivers will not work for it. I apologize for the inconvenience this causes. If you have any remaining questions or concerns, please don't hesitate to ask."
Their website says their Android Mobile SDK it still under development.