regarding #3: I have a well used 5 year old floorless MYOG tarptent with a noseeum (not nano) skirt that just lies on the ground. I routinely set boots, water bottles and other loose gear on it. No sign of damage yet.
So I don't know about nano ... but if (WHEN!) I make a lighter version (spinntex and nanoseeum), I'll likely treat it the same way.
But I wouldn't use any kind of mesh for a sod cloth on a shelter that will be used in the snow. That's not likely to last long and even if it did, it'd be a real pain in the backside.