Yes, any type of audio that’s not bitstreamed goes out as PCM. So stereo Flac should work fine for analog PCM.
Thank you.
Back to this possibility, which I think is still the ideal outcome, I found a nice workaround for the moment – the Audio Profiles addon for Kodi.
At present, since no auto-selection based on audio channel count is possible (although it sounds like it may become possible with Kodi 19), one has to manually switch the audio setup for stereo or multi-channel playback. For movie playback, I just folded the profile switch (and going back to stereo) into the activity for the Logitech remote.
For anyone who hasn’t already tried it out, Audio Profiles is a really nice addon!