Our team replied:
Content within a Screens app is HTML. As with any HTML app, the HTML content can be written to load content dynamically (client side). You can also leverage contextHub to personalize a specific piece of content to display based off a value changes in the ContextHub data layer & a client side script doing an external lookup can change these values… effectively allowing for personalization. On a Server level, you can use console scripts to change values within AEM itself… the players are designed to ping the server every 5 seconds to get updates so changing the correct value will cause the player to request updated content.