Temps hit the high 30s today in a light rain so I chopped out all the
ice. I bailed and replaced about 75% of the water and found all fish
surviving.

I want to try this as minimalistically as possible, so I will auger
holes like Koi-lo suggests and not buy heaters and air stones. As I
know they can make a month, and now that the water is freshened, I feel
like I'm safe into mid-February. Then I could do a water change and
coast from there into the Spring.

With the way these six goldfish fought off racoons all summer and
handled this cold snap I'm starting to think there isn't anything they
can't do. I'll auger, but I will not bring them inside or buy anything.
It seems like cheating.