Ive been using shurflos for years.
Ive never had a problem with them freezing or any tubing to burst because of freezing. They will pretty much run dry once the temperature drops and the switch turns them off if you set it correctly. the sap will freeze in the tubing and the pump will be fine. All of mine are in Black plastic containers. The sun or the radiated heat from the sky hits the box and gets it warmer before the temp probe kicks on with the air temperature.
so long story short, you are over thinking, no need to stress.
2022 4x40" RO, Welch 1397 Vac Pump, 3 Guzzler Pumps, Lapierre Releaser, 1100 taps
2021 Twin Baby Boys, Close to 650 taps
2020 Upgraded RO to 2 post and 7GBS Pump. 265 taps
2019 Smoky Lake 2x6 raised flue, Autodraw system, Maple Jet Filter Press, a beautiful new bride to be my sugaring partner :-)
2017 Expanded Sugar Shack, new 2x6 with float box, NEXTgen Maple RO, 250+ taps, still on sap sacks
2016 Sugar Shack, 2x6 evaporator, 160 taps, all on Sap Sacks
2014 110 taps
2013 35 taps