The new 45 north pogies have zippered vents.  Most of the pogies I make are upcycled kids' jackets and so they are at least somewhat breathable.
I haven't had a big issue with my gloves getting wet - I often ride barehanded, but even when I wear gloves, I can ride for days with dry hands.

Goal zero makes them.  I have one to go withmy solar panels.  It is good for at least 2 iphonecharges.

For just myself, i try to keep my total weight, including bike, to 65 pounds for anything under 6 nights.  When I am with someone, that weight limit goes up.
Mike Curiak has few good things to say about trailers in winter and I am inclined to agree, though I have used my chariot with skis to pull my kids a few times.  I tried a bob with a sled under the basket a couple of times and do not endorse it either. 
I use and reccommend a set of bags from Porcelain Rocket (handlebar, seat, frame).  I usually only carry my hydration pack on my back.

The Lake wides are not wide enough for my feet.  I have high arches and wide toes.  I generally use flat pedals and some old keen sandals or hiking shoes in the summer.  I like clipless just fine, but I wont sacrifice shoe comfort to get them.

Nick, enjoy your trips with your kids.  Mine have been backcountry camping since they were weeks old.  This trip was great for them, and Tadhg got much better at riding, it was just a little more technical than I anticipated.  I have taken them both on rides before, just nothing quite this long or rough.
The kids take on it all should be ready some time early next week.

I was hesitant to post this on here, but i think it illustrates the family-friendly nature of bikepacking.
This is a writeup of our trip from 2 weeks ago.
http://coldbike.wordpress.com/2013/03/11/winter-fatbikepacking-with-a-9-year-old/

Thermarests are slow to inflate and don't self inflate at all in the cold and have no insulation value if they leak.  The valves are hard to operate with mits on.
Closed cell foam has really good insulation value for it's weight and is really fast to set up and take down.  The folding style tends to be easier to set up and stow when it gets really cold.