Cool trip! That's a hefty day- I've had similar trips myself (78 miles and 14,000 ft in 48 hours was one). I've also been planning a 3x50 trip for awhile now- just got sidelined by life. But I've spent a lot of time planning and considering my hallucinations at mile 47 on a mega day.
With a day like this, you'll likely have very short stops. You probably have a schedule and I'd highly recommend that- I usually do 3 hours- 30 min break, etc. and I plan for my pace (I budget 3.5 while walking, knowing that I'm often faster, for example).
Also, you'll want to be prepared for exhaustion and the resulting mental breakdown because when it hits, you stop being reasonable. I even schedule my food along the way on a piece of paper to keep me honest. I'd also definitely consider something warmer in case you break down (mentally or physically). The bivy is a great idea, as is your vest and balaclava.
Also, my experience is that when hiking all day at this pace, you want the same foods that ultra runners use. I've settled in on Hammer Perpetuem which I mix in the field. With a day as long as yours, GU will give you spikes but you need a solid base of protein and fats as well. Accel Gel is much better for endurance because of the protein- highly recommended.
If you really want bag food, you could get one of the new no-cook Mountain House meals. They're good and it's only one night anyway. That way you could trade the cooking gear for that bivy and still be sub-4 (I go sub 4 on trips like this too).
Last, you want to be effecient and 14 oz poles are not effecient. I'd seriously consider a set of Gossamer Gear Lightreks or BMW Stix. If you have the cash, the STIX are the Ferrari of trekking poles. I honestly believe that they are a major part of my 40-50 mile days. In a hike this long, you want to have light poles in your hands. I believe that this is the greatest change you can make.
BTW- the weight on you Vitesse must be per shoe, right?
Man, this trip is awesome! I'd love to hear how it goes!!!