HX011 Polaris has this trait:
MY FATHER'S LEGACY: Once per turn when an opposing character is placed, after resolutions you may place that character up to 2 squares away from their current square.

So would an opposing character carrying another character be considered placing? Like after they carried, Polaris could move the carried character 2 squares away from the other character?

Yes, carrying places the carried character, so her trait would work.