Most of mopidy doesn't need dbus, so even on Linux I wouldn't assume it or add it to install_requires, unlike for mopidy-mpris. On Linux, even with the dbus library and daemon available, avahi may not be present. None of these should stop the frontend, of course. A good reason to split this up would be to take different actions for the different problem sources. Logging and moving on seems to be the appropriate response to all of these, however.

It would be a valuable addition to try Bonjour, too, perhaps through [pybonjour](https://github.com/nickstenning/pybonjour).