Might be worth a shot but unfortunately Octoprint recommends at least a Pi 3. I tried it myself on a 2B and had nonstop issues with print quality from stutters while the Pi was sending gcode to the printer. As soon as I swapped to a 4B the problems disappeared.

Plex allows you to add a list of local IPs that can access your server without authentication, just have to be sure to do it while your internet is up or else you won’t be able to log in to edit the setting.