For us non-metric users, -5C is 23F; 10C is 50F. So that's what we're dealing with.
I can't argue with your gear selection. Everything is nice and minimalist. Like I said in your earlier post, you can't go wrong with that setup. You'll be able to stake the shelter down, crawl in to erect the pole and then deal with any wet clothes, guylines etc. While this is (theoretically) doable with a poncho/tarp, it is of course harder because you are wearing your shelter. I have not been able to use my poncho/tarp and am a current novice with tarp camping, so I cannot truly question your judgment. The process of concern for own's own safety is the product of a rational mind, so said Joseph Heller.
Considering the posts re: Neoair, good decision to supplement it with your Torsolite. I would sleep without as a test of the new pad.
A few comments:
1. Pack liner?
2. With full fain gear, that is a nice light setup. Does your jacket cover your crotch/butt that is not covered by the chaps?
3. What guylines are you using? Cordlocks or tensioners?
4. Torso layers in order of lightest to warmest: MEC wicking, Thorofare, MEC Mid, Arc'Teryx, Skaha. Can you layer the O2 jacket over the Skaha? Whare are the MEC and Arc'Teryx pieces made of?
5. windscreen/caldera cone? Alan Dixon, and others, swear by them for efficiency.
6. What about a wide-brimmed hat or a baseball-style cap? Sunglasses?
7. WP sack for camera?
My brother and I hiked the SHT sobo in 2008; it took 11.5 days and we finished on Memorial Day at about noon. We were both carrying full rain gear and we slept in a DoubleRainbow. We donned jackets for the rain, and it was not needed for the foggy, final day. It also rained overnight night 10. It was done by morning, but it was chilly.
We camped at the northern terminus the day before beginning (Day 0, as we called it). There was frost on the ground when we woke up. Weather was very dry, and we were rained on twice and had one very misty morning. The rain was all just drizzle and nothing fierce. It did snow, too, but it was more like small crystals and not flakes. It was light but windy. We did wear out rain jackets occasionally as windshirts.
So far I have avoided hiking in a crazy storm on SHT. It did rain on my father and I last September around Bear/Bean Lake. It was also sufficiently windy. Had I not been with my father (it was his first hiking trip), I would have continued. I was in full rain gear (eVent jacket/Precip pants). It was also getting late, dark and it was about time for supper.
The 2008 SHT hike was before I truly discovered BPL, and the hike with my father was UL in spirit if not in weight.