Thanks fellas.
Frame arrived yesterday, after shipping on the 23rd. Was packed really well, and the frame is *flawless.* I'm really impressed. Managing file size to post photos is a pain. Here's a link to the unboxing pics.
https://photos.app.goo.gl/PTrEepQeP5n40QRl1 Build List
CS 496 Frame
Fork - Fox float 34 27.5+
Wheels 40MM carbon rims from carbon speed + DT350S + spokes
Cassette - m8000 42 tooth
XT boost 175mm Cranks
30 Tooth raceface chainring
XT 11 sp Derailleur
XT 11 speed Shifter
XT brakes
XT Rotors
XT Chain
tires - Trax Fatty
Bars - Renthal fatbar carbon lite 10cm rise
Seatpost - Fox transfer 31.6 internal dropper 125MM
Wolf Tooth lever for dropper post
Saddle - WTB Volt Pro
Stem - Race Face XXMM
headset - neco from Peter
Bottom bracket Shimano bb94 (bb92)
Cabling
Egg Beater 1 pedals
Everything but the wheels should be arriving today.
Those links on fork options got me pointed in the right direction. I think the general consensus is that in the absence of a 29+ fork, the 27.5+ works with a really wide range of tires, even well beyond 3" wide. I ended up going with a Fox 34 27.5+ with 140mm of travel. I'm not sure I'll want that much travel once I'm dialed in, but the switch to 130 or 120 should be achievable for pretty reasonable expenditure of money and effort.