Your title and sketch name says “flow field” but your question says “like a mouse.” Which are you trying to do? Create a flow field, or create a mouse pointer?
When you say “the lerped position from the Kinect” it sounds like you want to find the center of mass of the Kinect depth image, and constantly drag an object (like a mouse pointer or a ball) towards that center of mass. Is that right?
Do you want the pointer controlled by a nearest point, like a projecting hand, or do you want the entire depth field – like three people’s bodies, and the pointer falls somewhere between them?
You can also use blob detection with opencv or boofcv and find the center for each blob.