Hmm..I think the idea about linking devices on the same Apple ID together is suggestive of a Google Assistant/Alexa competitor. From the rumors we've seen, one of Apple's stumbling blocks for one these home based devices is shifting from a device-centric to a person-centric model. For example, when you add a calendar item- to whose calendar does that go? If you ask it to play music, which person's music plays? This sounds like an important first step. Apple has also theoretically tried to distinguish between people (though it doesn't seem to work in my opinion). When I say "Hey Siri", only my phone is supposed to activate. Getting that right might help solve these issues too.