Hi Bill,
I read this entire thread today. I have learned a ton! I have been looking off and on for the past five years for an automation solution for the cable channel our church leases. I am not sure if your solution is a good fit for me or not; I will leave that up to you. Here is what we currently do:
One output of our BMD Videohub is connected to the cable company. During the week we have one instance of VNC looping a PowerPoint Slide deck saved as an MP4 with no sound. We have a second instance of VNC playing looping through a folder of mp3 audio files. This happens on a dedicated Windows PC (Cable PC). On Sunday at 9:00 pm we had been using our BMD Videohub to switch the input routed to the cable company from the Cable PC to our live broadcast feed. This is an instance of OBS on our Presentation PC compositing content from PowerPoint, live open captioning, a PTZ camera, and our audio mixer. This same live content is livestreamed to Boxcast though another VideoHub output to an encoder they provided. At the end of the live event we use the Videohub to restore the Cable PC content to our cable channel. Then at 1:30 PM a tech from second church in our community remotes into our cable PC via TeamViewer, pauses our audio playlist, opens a browser over our looping slide deck video and plays their YouTube live stream from the previous week. Approximately and hour later he closes the browser and resumes our audio playlist. At 3:30PM I connect via AnyDesk and open a single slide PowerPoint with a static image provided by third church in our community. This overlays our looping slide deck video. I pause our audio playlist, open a browser, load the sermons page from their website, and play the audio they recorded the previous Sunday evening. When their audio finishes, I close their webpage and PowerPoint, and I resume our audio playlist. I would absolutely LOVE to be able to automate this. I would also love to be able to add other content to our schedule such as broadcasts of special events from the schools and other churches in the area. I've never dared offer this without automation.
I have written a lot of industrial control software and a little PC software; I understand how software works, and doesn't, :P I think I could be a helpful beta tester if you think your program would be an adequate fit for us.