I'd have to say that the duckbill section is a little bit more flexible than the section that continues underfoot. The material is the same, but the sides of the boot portion add some extra structure that is not present on the duckbill itself. But not a huge difference, and there is still some flex at the toes. A very comfy boot, nonetheless.

Paul,
Like Jeff, I use the BCX675 boot, and have found it to be very warm. I have done 8+ hour days of mixed skiing/snowshoeing/climbing, in -15F temps in the Adirondacks, and have never felt my feet get cold unless at a dead stop for more than an hour or so. And I am a skinny fellow who tends to always be cold. Have also done 4-5 day self-supported hut to hut trips in northern Quebec with 35lbs of backpack with no problems.
I use these boots with the Karhu 10th Mountain Ski, which I believe is now called the Epoch by Madshus. Together with the Voille cable binding, I am convinced I have the perfect setup. This boot and binding combo is definitely rugged and stable enough to drive my skis into perfect tele-turns on the steepest pitches, in all but the very deepest of snow. Then you'll have to work a bit to power out your turns. So they should be able to handle the burden of your heavy pack, and still steer nicely without any problems. The overall light weight of this setup combined with the reliable bite of the waxless fish-scales cruises through mixed up-and-down terrain, where my skinning friends on "lift serve" telemark gear struggle, suffer, and lag. For the final steeper ascents, I do ultimately put on the skins because most ADK skiing is on narrow densely-forested trails, with few possibilities for traverse when the pitch increases. That naturally means that the descents can be technical and fast, down the same narrow steep trails. And this setup delivers the maneuverability to get down safely. No room for tele turns?...no problem. Why not pull off a series of quick parallel turns and a hockey stop to check your speed. The boots can certainly handle it. And just as an aside, I also sometimes take these to the resort and tele ski alongside my friends on more rugged equipment. No problems.
Also wanted to add that they are so comfortable day after day that I'm sometimes tempted to use them for summer hiking, but wouldn't want to risk damaging the attachment pin-holes (plus they'd be way too warm). The heel groove and duck bill are a perfect fit with the BlackDiamond Sabertooth Pro crampon. Also, no problems with the MSR EvoAscent snowshoe. Can't recommend them enough for your application.

Hmm...but how well would the Smith Maze protect my noggin against falling rockand ice from overhead during a vertical climb segment? I'd like to carry just one helmet if possible. I looked further into it and learned that the Camp Pulse is indeed safety rated for both climbing and skiing, but I could not find similar confirmation about this helmet.

I suppose they would be equal.

The Fischer BCX675!!! Amazing boot. I have Karhu 10th Mountain Skis (now called the Madshus Eon), with Voile 3-pin/cable, and there is nothing that this setup cannot do. I can ski past the skinny touring skiers at the resort, climb with light-weight ease and quickness, carve tele turns with the best of them, and even carve aggressive parallel turns through small moguls. In the backcountry of the Adirondacks (my preferred playground) there is nowhere that this setup (plus a pair of BD Sabretooth Pro crampons) cannot take me.

I use these with the Fischer BCX675 backcountry boot, which has a duck-bill front and a heel groove in the back. I use these boots with the Voile 75mm three-pin bindings with heel cable, on my Karhu 10th-Mountain skis. With this setup, there is nowhere in the Adirondack high peaks (my backyard) that I cannot ski/hike/climb into in the winter.

I would second guess your Himalayan trip if you are considering using a soft shell as part of a layering strategy...completely defeats the whole purpose of wearing a soft shell.

Whether it is large enough for a weekend trip totally depends on what type of backpacking you do. If you typically bring a full bottle of shampoo and a mini camp-stove espresso maker, then I'd say no. But if your the type of person who only bring the one pot from your cook-set that you're likely to use, and who folds your insulating jacket to extend the length of a 3/4 length sleeping pad, then I would say definitely.
Years ago, I purchased a 2500cu in bag from EMS, thinking it would be a large sized pack for adventurous day hikes during precarious conditions where some extra safety gear would be nice to have. I had planned to purchase a full sized pack for camping in the backcountry. Being a procrastinator, and also being quite choosy, I never got around to finding a full sized pack I was happy with, and so I started trying to cram all of my stuff into that 2500 cu in bag. In the beginning it was a challenge, often requiring me to strap stuff to the outside. But that challenge created a subtle pressure that encouraged me to seek out smaller, lighter, more efficient gear, and also to trim down the amount of unnecessary stuff that I was bringing. Now I hike in late fall in the Adirondacks with 18 pounds of gear, and can cover much greater distances with ease, and ascend more technical terrain that the people who are buckling under the weight of their 45-50lb loads. Consequently I find hiking into the back country more enjoyable, and have not sacrificed any comfort.
Do yourself a favor, buy this bag, struggle to make it work at first, and then hone your gear down to a point of perfection. If you decide to get a larger bag, then the opposite will happen - you will find a way to fill it with unneeded weight and bulk.
cheers.
fs