Mine were in 4" pots @ 0F
From your videos you have square pots crammed up next to each other so there is little air space between the pots. And the dead air space there is could act as insulation between pots. But regardless the net effect could be similar to a larger container. They are also enclosed and not exposed directly to wind and snow.
So why don't you put some of your pots outside the greenhouse free standing without protection from the wind and snow this coming winter. Less likely to survive doesn't mean they won't or can't survive.