[wrxtasy]

So, it sounds like to have HD audio bitstream w/either CT's or fritsch's builds, you either need to disable amcodec and/or adjust refresh rate? If so, neither are desirable I think as this impacts other things (microstutters every 42 secs, 3D MVC, and just losing amcodec on an AMLogic box, which would seem to be its appeal).

You will not have to go about disabling anything, it will be all Automatic if you select HD Audio Passthrough.
amcodec is not disabled, its the Kernel Frame Rate Automation process that outputs nicely synced 23.976fps video that is disabled so it does not interfere with the HD Audio Passthrough itself.

If above is true, then decode to LPCM w/refresh rate & amcodec both enabled, seems the better choice. And, this was/is already working quite well. All this assuming I'm following correctly .

Yes as CT has said, turn off Passthrough and set then number of Audio channels for Multichannel PCM Audio decoding to be output. You will then get Lossless Audio and nicely synced 23.976fps video output.
Minus your HD Audio Christmas lights on your AVR winking at you