Good because women don't take kindly to comments about their weight. Unless you're telling them they look like they've lost some.
There's no holiday like Christmas on Asgard? Nothing at all? Nothing to celebrate or commemorate the birth of a christ like being? Or prophet maybe? Most places I've been all have their stories.
Because the biggest non religious Christmas thing is Santa Claus who started out as St. Nick who used to take toys to children for the holiday. The story kind of morphed from there. Parents tell their children if they misbehave during the year, then Santa will bring them coal instead of a present.