The heat pump wall units have a power disconnect switch mounted below them (required by code). That will easily serve as a reset if the esp locks up or something. My work bench is right beneath one of the units that I have removed the cover. I plan to do all of my testing there and go from there. I full anticipate pulling the cover a couple of times but want to limit how often I do. Might as well get the circuit right first time... that's easier to ensure is right vs. code.
I have considered mounting the ESP unit above the HP and still may but still want as reliable as I can get.
At the end of the day I'm not a EE so details of these circuits can confuse me. Seems like the logic converter is the best approach. As I was laying out the demo circuit on my solderless breadboard I started questioning the 10k pullups and wanted to check with people that know far more than I do.
It seems like the logic converters are in order.