The ideal Fatbike has 26×4.8in tires on e80mm (e=exterior width) rims and has no suspension. This bike will perform very well in snow but makes a crappy trailbike. The Farley comes with 27.5 Fat wheels. There are vey few 27.5 Fat tires made. So if you want a Snowbike, look for a different brand.
A 29+ hardtail makes an excellent Trailbike. However, a Plusbike is a crappy Snowbike. 3.0 tires just aren’t wide enough to perform well in snow. The 29+ Stache currently comes with i45mm (i=inner width) rims and 29×3.0 tires. I keep hoping that Trek will update this bike with 29×2.8 tires on i35 rims. A 2.8 tire-i35 rim does everything wider rims and tires do but with less weight and rolling resistance. An i35 rims also gives you more versatility and allows you to use 2.4 to 3.0 tires. While an i45 rim is only good for 2.8 and 3.0 tires.
There is really no way for you to get a bike that does both well!!!!!!
It it was me, I’d say get both. However, I’d get a 29+ full-suspension Trek Full Stache (which has i35 rims) and a Borealis Fatbike.