all issues were due to a router reset

Multiple things went wrong -

1. we could not ssh into the Raspberry Pi doing loop playout in the lobby in order to reboot it - for which we generally use the RaspController app.
2. we could not control our theatre lights - controlled using a python script as per this post.
3. The playout Amazon Firestick could not connect to the internet, so it was displaying "Home Unavailable" - the workaround was to long-press home, and choose MxPlayer from the installed apps from the shortcut menu.  

It turned out that all the issues were due to the Wifi router getting reset. Why? No idea. Anyway, filled in all the static ip addresses mapped to MAC addresses, as well as the gateway information, restarted the router and the devices, and all was well.