Thanks for your prompt reply!
Dual Kinect setup confirmed working! Thank you for the modification!
And as a reminder for everyone who stumbles here, you need each Kinect connected to a separate USB Bus (which is not the same as port). As it turned out, my NUC had only one USB Bus (and 3 ports), so I had to replace its inner wifi card with a miniPCI Express USB 3.0 controller. Even then, trying to plug in second Kinect (to whichever bus) would result in its disconnection/connection every few seconds. Plugging it through a USB Hub somehow magically solved the problem.