Sorry they are not getting in touch...
For the RGB light, Hubitat does have an HSV to RGB conversion here is a thread referencing it. I have not used it myself. You could always look at altering an existing ZigBee driver to add RGB support. Their ZigBee RGBW bulb code is here (already mentioned above it turns out).
@kkossev might know about the later two points. Hubitat also has sample code for an environment sensor but it does not include motion. I have had temperature and motion sensors in the past (most of my old ZigBee motion sensors also provided temperature). It sounds more and more like you might want to create a custom Hubitat driver as well.
