I don’t have a fat bike but I have a couple mountain bikes. I have a Trek Fuel EX 29er that I mounted 2.6” tires on. It’s not like those 4” tires but it is grippy. Regarding the night riding, I use two lights if riding a serious trail. I use a 1200 on the bars (2 beams) and a 700 on my helmet. With good lights, you will be able to see those limbs.
The guys who race across the Alaska tundra every year always win on 2.5 or 2.75" tires.
