When we build an API, all of this will be possible (DIY or otherwise…no intent to lock this down).
This is a relatively near-term objective for us–it enables tons of good user experience on a wide range of existing hardware, and also allows us to expand in markets that require home automation without necessarily taking personal ownership for integrating with each individual system one by one.
We’re thinking that API consumers will talk to the core via a network protocol. So a display could come up to the server and say “tell me what’s playing on zone X and subscribe me to updates so I can know when that changes”.
Obviously we want to do much more than just now-playing displays. Integrating with external volume controls, source selection, standby controls, and physical buttons in the listening area are important, and we’ll probably do some list-based browsing/searching too.