Simple Wallboard Displays, not so simple.

I'm looking to solve what I initially thought would be a simple internal problem. I didn't think I'd be the first to want to do this, so I'm posting with the hopes that someone has already worked this out.

We have numerous wallboards (40+ inch TVs) all over our company. Exec offices, warehouse, marketing, production, etc. Each dept wants different powerbi 'screens' to rotate thru their respective displays.

Examples: Warehouse wants to know the count of orders left for today vs how many they did yesterday. Marketing wants to know how many tweets in the last hour. And so on....

I'm looking to embed all this in an intranet site. Which sounds simple until I started digging. I know there are 3 ways to embed. The publish to web obviously won't work as we don't want company metrics availible to the public. This leaves Rest API and PBI Embedded. These both leave me with issues:

1) For costs, I'd like to use a single PBI account as a service account to access all the info. As it will need access to all Dept reports, dashboards, etc. This is an issue depending on #3's answer.

2) PBI Embeded pricing model. Some 'screens' don't need to update more than 8 times a day. Others I need to throw live data and update every 5 minutes. I'd rather not have a huge increase in costs to simply show metrics on our walls.

3) Do I have my Dev guys just create a simple web app that calls the embedded data? Can that be coded to call specific defaults reports/dashboards, or does the user simply default to one and user interaction is required to change?

None of these displays will be interactive. Hell I've even considered maybe scripting screengrabs at this point. I feel like there should be a simpler way to display non interactive data to wallboards. I've got other non powerbi solutions, but our company really wants to stay with the uniformity of it.