I can confirm that the Nexus 6p, out of the box, will run the wifi hotspot on VZW UDP, on both 6.1 and 7.0.
I can also confirm that the Nexus 5x, out of the box will NOT run wifi hotspot on VZW UPD, without rooting and modifying build.prop (easy to do if you are bootloader unlocked).
Reports are that bootloader will be locked on Pixel for phones sold by VZW. I'm not very optimistic that wifi tether will work
I have an upgrade on VZW - which I wanted to use for Pixel, but might have to buy Pixel (or iPhone?) and trade/sell to get an unlocked Pixel, which should be bootloader unlocked, but probably won't have VZW wifi calling available.