can run two controllers on my Zwave network at the same time. Is that actually possible long term (and not just for firmware updates)? Could I potentially use Smartthings to control the “remote” things, and use Home Assistant/OpenHab/or Homesseer on a PI with my new Zstick at the same time to control things locally?
Probably not the way you are imagining. See the brand new FAQ. (The topic title is a clickable link.)