Previously I have had success implementing PM2, but not currently.
My node app does run just fine if I start it manually, but nothing I do gets it to run
Ok, I got the answer after posting an issue to the pm2 github issues page.
Sharing it here in case anyone else finds themselves in this situation:
https://github.com/Unitech/pm2/issues/4113
(Basically pm2 3.2.5 introduced a bug that causes this issue in Windows. My dev install was 3.2.4. The issue was resolved by reverting to 3.2.4 in production. Simple process, see instructions at link above.)