Bummer, Apple's HomePod speaker may not let you stream Bluetooth audio
While lock-up to the Apple ecosystem could pretty much be expected with ease, a full-bore such effort comes as a tad of a surprise. Thus, while you will be able to stream tunes via the new and improved AirPlay standard, Bluetooth is a no-go, it seems, even from your iPhone, let alone another handset.
Other options include Apple Music, your library matches in iCloud, Beats 1, podcasts, and the AirPlay's "other content" option likely means stream other music subscription services in a barebones manner. Apple Music subs with Android may have to look elsewhere for their smart speaker needs, it looks like.