What are you using to capture the XBone, for use in OBS?
You'd set a different mic device in OBS' settings, after linking your XBone headset with the laptop. Assuming you can do that; not sure if that one's possible (to have it linked to both the laptop and xbone, assuming you want to use in-game VoIP).
Connect the kinect to your laptop then, with the appropriate adapters and/or drivers. OBS can't grab the kinect through the xbone. If it's a V2, I'm pretty sure it won't just natively plug in over USB like the V1 can.