I bought this with the "USB-C/Thunderbolt3" dock, and despite our lack of TB3 support, everything but the GigE on the dock works to a usable extent with 12-Current r333447
The docks USB ports work right out of the box.
The docks Video requires ports/graphics/drm-next-kmod, and you must kldload i915kms before you start X.
NB1: Make sure you don't mix kld's in /boot/kernel and /boot/modules. Easiest is probably cp /boot/modules/* /boot/kernel
In case you encounter kernel panic when loading the i915kms.ko module add kern.smp.disabled=1 to your /boot/loader.conf.
Wireless is i8265/iwm and it seems to work, I use this in loader.conf:
Suspend/Resume seems to work from Xorg, if you disable TPM in the bios.
Untested: Camera, Microphone, Fingerprint reader, Smartcard reader, SD-card reader.
Overall impression so far: Good, would recommend to current-running hackers.