I definitely second bring more insulation. Jonathan Ryan on this site has posted 2-3 gear lists of previous Presidential Range trips, and he usually has 6-7 layers, including a puffy vest and patagonia DAS jacket. Maybe adding a Logan vest could help you, or a full on synthetic parka. Also Platypus in sub 20* weather is going to be tough, and I've also cracked sigg bottles winter camping, but they still remain my favorite, and I will often carry them in a chest pocket for accessibility and warmth. I've read that Dromlites are effective, that may be handy for having 4L of water ready in the morning in your bag rather than in a more time consuming fridge. You could get some aluminized bubble wrap and insulate your platy for the winter as another option.
For 3rd day food, maybe consider GU packets or the like, they are very light and what are the chances your stomach is up for something like Ramin after being in a coffin cave? Alpinists swear by them.
Ice climbing may require more glove liners, Jetboil will work if you are carrying the canister in a pocket, make sure that it is unlikely you will run out of dry socks and gloves, and know that you can dry them by body warmth.
For what its worth I have used a Big agnes Aircore pad down to -5ish, and its a 32* pad, and luxurious, but I've also heard people getting cold on this pad, YMMV