FWIW this long after the original post…that LightCarbon frame looks fine.
Keep in mind a 100-120mm suspension fork would substantially change those numbers and probably drop a degree or two off the HA. I wouldn’t suggest anything other than a Mastodon or a Wren for deep cold snow riding, my experience with the Bluto has been subpar to put it mildly. Sluggish damping, stanchion icing/sticking, air seal blowouts and eventually massive bushing failure.
If you’re looking for a warm weather fat setup that’s a different ball game….you can basically set that up like a hardcore hardtail if you want with progressive geometry, a long travel fork, 27.5 wheels and medium sized tires etc. but for snow riding you want almost the exact opposite. Not too slack, relatively balanced instead of back-weighted like a MTB, and sometimes rigid forks actually make more sense.
Personally I’d love to see a “catalog”/open mold fat frame that was confirmed to fit 27.5x4.5 tires. That’s where it’s at for snow riding on mostly groomed trails IMO.