Thanks for the comments: very helpful! As I said in another comment, Vue looks increasingly the best choice given the use case and my experience. It's actually

Thanks for the comments: very helpful! As I said in another comment, Vue looks increasingly the best choice given the use case and my experience. It's actually going to be everything except streaming video; going to send through audio, image links, and some extra data, and mush it all together at the client. Fortunately I don't have to worry much about adaptive bandwidth, since for the target audience we can just kick them off if they don't have enough bandwidth... if they can't get the 24 kbps for the Opus stream, then too bad! I'll have a good look at HLS.js. But I'm prototyping out using WebRTC to do it rather than HLS, given that iOS 11 will support it natively. Unless people have a strong argument against doing that way...