I'm surprised that so few people seem to be interested in this amazing tablet. I've had my fair share of Hackintoshs, but this is by far the most versatile and amazing one. Apart from minor things (mobile data, microSD, Thunderbolt) things work wonderfully, including the stylus (I've tried both the original one and one from Lenovo, and the latter seems to work more smoothly).
What I especially appreciate is gesture control with up to five-finger-gestures. Awesome.
@jhax01 Thanks a ton for your efforts with getting this tablet working with OS X so beautifully and for putting together the instructions.
As far as Thunderbolt is concerned I am not sure why it is not working with Sierra (tried the 'HP Elite 65W Thunderbolt 3 Dock P5Q54AA with 10.12.4), as 10.12 should be able to cope with it. If that gets resolved at some point the Elite x2 is going to replace my 'sierra-d' Intel NUC. Until then I am back with 10.11 for the reasons mentioned in the original post.