In an hour of darkness a blind man is the best guide. In an age of insanity look to the madman to show the way, so follow me
Can't remember where I read it, maybe backpackinglight, but sounds like a good idea. Single loop of guy line around stick or rock that you bury in snow. Bring working end out of snow and tie a slippery half hitch back near the tarp. Tension of all guy outs still accessible for adjustment. Obviously the buried "deadman" needs to be pretty solid at this point. When ready to pack up, untie the guy and pull line out, leaving the stick buried. I have not personally tried this, but it seems to make sense.
I will see if I can. I did exactly what you described a couple of years back. The snow was three feet deep and the wind was a constant 20mph. So dug a snow trench under the hammock and piled the snow around the bottom of the tarp. It was sealed off extremely well and I was warm all night long. Didn't even feel the wind at night. Heard it but didn't feel it.
Two things to add here. Remember that you will usually be suspending from trees. And in the winter there can be tree wells or the snow around the tree will be weak/hollow. So you might want to stomp the snow down around the tree and give it about 15 minutes to set up before you stand on it. If it sinks down, then you may need to dig down under the hammock because you won't be able to suspend it high enough on the tree to clear the level of snow on the ground. If that's the case, clear under and in front of the hammock on the leeward side so the snow on the other side acts as a windbreak.
Also - be sure you stomp out the path to your "nature calls" area before you go to bed. By the time you have to use it, hopefully your stomped out path will be solid. It's a pain to have to "take a walk" at night be sinking into knee depth snow.