For what it’s worth, the modular and granular synth stuff is working fine for me on El Capitan 10.11.6 with the latest 4.16 release and either AudioMixerCoreAudio in the .ini or the -audiomixer switch on the command line.
Sorry that isn’t much help, but at least it answers the question of whether it works for anyone on Mac at all! My biggest problem is that it doesn’t choose the system default output device, defaulting instead to the Mac’s built-in audio (which I’ve asked about in a different thread), but what’s been said in this thread makes me think that some Mac-specific options for that might arrive in the future.
Are you on Sierra, Steve? Might be worth trying on ElCap if you have an old bootable backup lying around. I’d be curious to know if upgrading to Sierra will scupper the 4.16 audio stuff…