The big problem here is not how the plumbing it done but the failure of our power grid. When people are without power for days and temps are way below freezing, pipes WILL freeze.
I ran PEX when I built this house, and I made sure all the supply piping was inside the insulation, but it froze after the power had been off for a while. Took a couple days to get the water running after the power came back on. I was luck and only lost the on-demand water heater that is mounted in an outside wall. A new will be be here tomorrow.