1300g? I'm going to go ahead and be verrrrry skeptical of that weight. That's phenomenally light for a fork of that size. Only things I've seen in that range are the old RockShox SIDs with the 28mm stanchions, and I'm quite sure you don't want that on a fat bike. I had a set of SIDs back in the day and when I hit the brakes I could see the front wheel flex backwards nearly 2 inches. *yikes*
Agreed about being super skeptical of that weight, although it does support the idea of fully carbon lowers, no?
In theory, yes, but I can't imagine the first carbon lowers that we'll see would come from a Chiner vendor. If it's truth, though, that could be quite impressive. I don't know as there's anything to necessarily preclude the carbon lowers - the bushings are press fit into normal lowers so could be press fit into carbon lowers as well.
Out of curiosity - did a quick search and found
this. Billed as a "full carbon" fork but has metal stanchions and dropouts - but still, carbon lowers. Also, 1530g weight which is far more believable.
Also -
scroll down around halfway.
So it's not outside the realm of possibility.