The Murmur is still in the mail, but my calcs say everything will fit inside (fingers crossed).
I have used this clothing system comfortably with daytime temps in the 40's and nighttime temps down into the 20's. I try to keep moving during daylight hours when it's below 50 degrees. The bivy and tarp overhead contribute to warmth at night, I always sleep in my base layers, and I can add the vest if necessary.
The fleece cap is a good suggestion, and something that I frequently add in the shoulder months (along with light gloves). I find that the Buff works pretty good as a hat when I need something extra over my ears and forehead (not unlike my avatar picture). The only real additional to make mine a full 3-season list would be dedicated rain jacket/pants, fleece hat, and gloves.