Your set up choices seem well reasoned for a first set (have you looked for a used set?), and this discussion that follows is a lot of personal preferences so just add my input into the other opinions you've heard. I think, like regular skis, if you use them frequently, they will wear out and you'll change to a new --more fitting-- set up in just a few seasons after this initial purchase, so don't get too bogged down... That said. Cost, outing type, and boot function all seem like factors you've considered.
Waybacks are not the only ski in its class (lightweight, and not-as-stiff). La Sportiva and Dynafit also have good skis like the Wayback, but for an 'all-conditions' ski you want some rigidity (depending on how good of a skier you are). Verdicts or Aspects, Dynafit, or other slightly stiffer skis aren't a bad option for a 1 ski quiver. BDs are on sale right now. Keep in mind that these days ski length is not determined by body weight as much, its more about the shape of the ski, and terrain you intend to ski. For an all conditions ski or a couloir ski, longer is not better. In fact, I'd go wider before I'd go longer. Short skis allow for tight/jump turns in couloirs, or on variable snow. If you are thinking about adding weight in length, think instead about adding the weight in width, width works better in powder. Whether longer or wider, a ski should most likely be more stiff the bigger it is. I would stick to generally what you are skiing now, depending on the shape of the ski. Waybacks should probably be about the length you normally ski, BUT, again, its more about use, not body weight as has been emphasized in the past...
Climbable boots are key, and are perhaps the most important piece of equipment for ski mountaineering and there are many to choose from. Certainly try a bunch on prior to buying, and consider mileage/time climbing vs mileage/time skinning vs mileage/time skiing for that decision. Stiffness and ski performance go up or down together. Your boot decision affects your ski and binding choice greatly. OR, in other words, you outings affect your boot choice, and your ski shouldn't be too much or to little for your boot. I have both a stiff 4 buckle boot, and a flexible 3 buckle boot, and both are Dynafit binding compatible.
I use Mt. Bakers (old Waybacks) with Dynafit for stuff with a lot of carrying or long miles, and a beefier set of Dynafit bindings on some BD Amperages for touring with less carrying and less daily miles. Some folks are not concerned with a lot of weight, because their intent is to enjoy the downhill. But for true climbing weight is huge, and you WILL feel the difference. For more miles I'd suggest checking out Dynafit's various bindings, (although many folks would be jazzed about the set up you are talking about), Dynafits are generally better for most uses (and eventually possibly look at La Sportiva as well once they develop them a bit more and cost comes down). They are light and durable.
Some guides and other true ski mountaineers solely use a racing or near racing set up, or even a beefy xc set-up for long traverses. Or even skating... So good luck with all the decisions.