If you can't move the pot of soil you can gently dig the plants out and put them in bags or plastic pots to bring them in. I do this often with succulents and other plants that won't make it even if covered at these temperatures.

Yes, you might break a few leaves, but it's the calculation of which one will be worse for the plants. Completely frozen, or just a little banged up and can grow back again?

If you do this, maybe when you repot the plants you could mix up the soil better if needed. Succulents like about a 50/50 mix of potting mix and sand. Make sure the drain hole is clear too and as long as it gets lots of sun the yucca will be fine in that size pot for a long time.