Help for architecting a MinimServer solution on MacOS

[Cebolla]

(16-03-2018 13:32)eschreye Wrote:  Clearly, I would prefer to stay away from solutions à la iTunes, foobar, MediaMonkey, JRiver Media Center which require (my understanding) processing of metadata into new libraries.

No that's not correct. There is no "processing of metadata into new libraries", if you are using them purely as UPnP renderers, so:
iTunes - irrelevant as it doesn't support UPnP;
MediaMonkey - can be used as a standard UPnP renderer, but is Windows only and doesn't support gapless playback as a UPnP renderer;
foobar2000 - can be used as a standard UPnP renderer (with the foo_upnp plugin), but is Windows only;
JRiver - can be used as a standard UPnP renderer and Mac version is available.