I figured it out - user malfunction on my part, I wasn't cloning nodebb into the correct "node" user home folder properly! 🙄 Stooopid I know...
Extra to note - I also ran into failed setup when using nodejs 12 and nodeBB 1.12 (think hey lets go with the latest of everything!) and this was after correcting my user folder error, so decided to revert to a nodejs 11 and nodebb 1.11 stack.
The forum has successfully rebuilt and restarted, no errors and the plugin is doing it's thing!
Can't really debug as I don't know your app, but if there's a stack trace, it'll show the problem, likely.
Also you probably want to set the cookie after passport does its local authentication, otherwise a malicious user can attempt to log into an account using a wrong password, but still get a valid jwt, and then log into the nodebb forum under that account.