[popcornmix]

For Raspberry Pi, are you saying for 3D ISO, we're getting HSBS rendering/output? But, for Pi and MVC MKV, we're getting full (#1, frame-packing)? My PJ indicates it's receiving "frame packing" for both containers.

No. It doesn't matter where the video comes from, if you can decode the MVC, then you will have the full resolution (i.e. 1920x1080 for each eye).
If "Use Full HD HDMI modes for 3D" is enabled the Pi will output in a framepacked mode which maintains the full resolution.
If that option is not specified then you will get HSBS or HTAB and so half the resolution.

"Use Full HD HDMI modes for 3D" is a Pi specific option. It merely sends a flag to the firmware to request the framepacked HDMI mode.
The issue with Android boxes is there is no standard way to request a framepacked mode and that would have to be done outside of kodi
(either in kernel or firmware). It is possible for manufacturers to implement their own custom APIs for this, but until Android makes a standard API
this will need custom builds for different devices (assuming the hardware is capable of supporting it and the manufacturers implement it).