I live a little north of you in Washington. So I thought I would give you my take. We both deal with cold, damp, snow, and fog. I have a WBB 1.1 DL and I love it. For your weight and hight the WBB 1.1 DL should be fine. I was shorter and heavier for a bit an I was fine. I used pads up until recently. A Pad works well in the WBB 1.1 Dl. I would advise getting one from REI and not Walmart. The REI blue foam is much more flexible i.e. fits in the hammock better. I also used a car windshield reflector in warmer temperatures. That said An underquilt in cold weather is awesome. Someone once said pads will keep you from getting cold but an underquilt will keep you warm.
As for tarps, yes the doors help keep you warm. If you are humping everything on your back you may want to look at lighter (read more expensive) silnylon or Cuban fiber. But you don't have to spent the money. I have an older Gear Guide 12x12 that I use in winter. It is a bit heavy to backpack for some. But I manage it for 5-10 mile trips and I'm an out of shape slug. For warmer weather I use a 10x10 sheet of tyvek because I am cheapskate. But in the cold I like having a tarp I can put in to tent mode.
Regarding whoopie slings, I am not sure I can help you there. I have the standard webbing and I am fine with it. I can't seem to wrap my head around what makes whoopie slings a big deal with some folks. But I am a bit thick sometimes..
Hope this helps. Feel free to ping me if you have any questions.