If he's got a pack liner, why does he need a pack cover at all?
I'm not sure I'd suggest the neo air small for snow camping, you seem to be something of the exception to the rule in regards to the neoair warmth Dan(read: mutant)... ;)
But bender can always make you a smaller lighter pad.
I'm guessing the reason he doesn't ditch the bivy is because he has the hexamid without netting.
Here's something I learned from my recent peru trip: Never leave the bug bivy at home and only use a tarp in giant tarantula country! Oh yeah, and I've got literally over 100 black fly bites that are still healing.
My one suggestion: Ditch the stuff sack for the quilt, it's redundant. Just stuff the quilt in the bottom of your pack liner and let the rest of your gear compress it. That helps you avoid needing to use any compression on your pack, and keeps your quilt from needing more loft time from being compressed. Win Win.
I generally use my pack liner, maybe one stuff sack for strictly organizational ease, and then a blast food bag, quilt and any extra clothing go in the pack liner/compactor bag, everything else goes in either the stuff sack or just the pack body if it's ok to not get wet. 9 times out of ten though it's just the liner and the food bag, and I've never had a problem with that. That being said, I understand the need to separate some stuff
to keep you from going insane.
Cheers Brian, your gear list is pretty locked.