With boots, width does make things difficult. The short answer is that, no, neither the Invernos ($290; www.scarpa-us.com) nor the newer, lighter Alphas ($350) are particularly wide, so you'll have a difficult time fitting into a pair. If by chance they DO fit moderately well, I'm inclined to side with the Invernos as these are a little warmer and a little more rigid for straight ice climbing. The Alphas are better on mixed terrain.
Overall, for a week in weather that cold, a double boot clearly will be the way to go. Some of the newer hybrid boots would likely workexample, Salomon's Pro Thermic ($380; www.salomonoutdoor.com) or Tecnica's T-Rock Thermal ($340; www.tecnicausa.com)but I think you'd be happier in a full plastic double boot such as the Inverno or the Koflach Arctis Expe ($355; www.koflachusa.com). Given the nature of a trip like yours, you'll likely be doing a fair amount of standing around, and I should think warmer will be better.
Still, the fit issue is difficult. You may have to buy a boot that is one size bigger, length-wise, than you need in order to get the right width. Then you'll need to fiddle with socks, heel inserts, insoles, and other stuff to adjust the fit so you don't have too much fore and aft slop. It won't be easy, but a good boot fitter at a mountaineering store should be able to help you.