Apple’s new Airplay 2 is hinting at multi-room support and perhaps integration between ATVs and HomePods.
How does SimpleControl fit into this?
For example, if someone says to his HomePod, “play album X in the living room and family room,” that may get the ATVs in those rooms playing the right content. But, ideally, SimpleControl would get some kind of notification from AirPlay2 (if possible) and switch on ATVs and receivers in those rooms.
A bit too early to say. Right now HomePod wont even run apps, so its Siri integration would be significantly inferior to that on normal iOS devices. Of course, it’s also 6+ months away, so anything can still change.
Yet, the last pattern like this was the introduction of Apple TV which was presented to developers as a new platform in June and shipped to users in late Fall. Thus, one would have thought Apple would pre-announce the ability for apps to run on HomePod if they intended to do so in the next ~9 months because it takes developers a long time to build such apps. So there is every reason to believe HomePod will not have Serious Siri integration until at least June 2018 (next WWDC when Apple would traditionally make such large developer-related announcements).
Specifically though to your question, there are other APIs related to Apple Music and such that are rumored to be announced this week that may relate to specific AirPlay/Apple Music scenarios, and we’ll evaluate all those things. Since such APIs would be used from an iOS device unlike the Siri API HomePod gap, it’s quite possible there are things to explore there.