Re: snow boots and braces
It's definitely a nightmare trying to find boots that work over braces. My daughter tried without braces but has more difficulty walking that way.
We always get one size too big and make sure that they open all the way down to the middle of the foot. If the tongue is attached on the sides, just cut it apart, so that you can open the boot completely. I usually buy something cheap from Walmart, because it's not like she needs much warmth or support in the boot -- just stability and preferably some waterproofing -- so then you don't feel bad about the modifications.
I hope that helps you to find something that works for you.