I’ve never had to deal with this issue before so I don’t really know how to treat this, my worry is that the dead flesh might just fall off and then you’ll have a special needs goose.
I’d do what the others suggested and keep them all off the snow, bring that goose inside while they heal, maybe spray some antiseptic of those feet so that an infection doesn’t develop.
I’ve heard of people keeping their geese in the far north just fine, maybe this is a situation of moist cold instead of dry cold? Really low temps are tolerated better if there’s no moisture, damp air chills to the bone much more easily, maybe they stepped into a water dish or spilt it onto themselves while out? Either that or geese aren’t as cold tolerant as we believe them to be, I know mine aren’t but that’s another story.
Different individuals probably have different tolerances too.