[liability]

mpv plays youtube links and many other websites (although not netflix or spotify to my knowledge) using the excellent youtube-dl. For my purposes it is more than sufficient, but as I said it won't be for everybody.

As to why I don't want google devices on my LAN, I'm sure you could already guess that the answer is the usual privacy/political concerns, which I'll not bore you with since you obviously don't care. There are however some practical benefits to my arrangement, particularly being able to play media served up by NFS (DLNA never gave me anything but grief and unreliability.) Furthermore youtube-dl supports a very long tail of sites that Chromecast doesn't (at least not without the jank of screen mirroring, which AFAIK only works for as long as the laptop being mirrored is turned on.)