Finally got around to upgrading to esxi6.7 today - but before I did that, I tried R151028 on it. Seems to work fine other than a few things I noticed:
1. The installer will boot off USB fine, but if you install to a USB stick, it won't boot after you are done. I think it is this bug:
Bug #8679: failed to attach AMD IOMMU - illumos gate - illumos
2. I wasn't smart enough to figure out how to make it boot off the onboard m.2 drive - again, it would install fine, but wouldn't boot afterward. Someone with more UEFI shell fu than me could probably make it work though.
Finally, I installed it onto just a normal SATA drive, and it booted fine. I installed nappit and everything seemed to work fine. I could see both the m.2 drive and the optane, as well as import the pool attached to the onboard SAS so I think it would probably work ok, keeping the above in mind.