Hi Alex,
You could probably do all this in one scene, which would fix the issue of data getting stuck in the Skeleton tracking system. also, entering a new scene restarts the OpenNI Tracker, which i try to avoid, wherever possible. If you feel you need to use multiple scenes, you could run the Kinect-Skeleton stuff in a background scene and send data through to the main scenes using Broadcaster/Listener actors.
As its for an installation, there may be an issue where the OpenNI actor gets a bit full as more people pass through. I know that you have it set to forget skeletons immediately when someone leaves the space, but sometimes the system hangs on to the data, just in case someone comes back and it can recognise them straight away. its worth testing with a large number of people - you may need to trigger the reset function when the number of new people reaches 6 or 8 or something. i think the 'bodies internal' count is the one that reflects this.
hope you are well, last week i designed a pull-up banner and some screen ads around a photo of you, Marianna and Efrat, all looking moody under a streetlight.
best, john