I think everything looks great! They should be fine because snow, and even ice, doesn't hurt plants, it's the super cold temps that do it. Around here, when the fruit trees have bloomed out and they're predicting temps down below freezing for most of the night, they'll turn on these big sprinklers on the trees so that they all get coated with ice. The ice layer actually acts as an insulator, keeping the blooms right at 32 degrees and doesn't let the colder air get to them. It sounds really weird, but apparently it works.
HHMMMM, I wonder if I should water them tonight. Tonight it's suppose to be 25. But I've always thought it stays warmer up here by the house. I'll cover the fern for sure again tonight, The MG seedlings is not that big of deal, but I'm a bit worried about the lilies, but they are right next to the house.
Becky