Hi Joel
Unfortunately there doesn't seem to be a way to access the values in other controls within a patch or the same or other controls in another patch on a BC.
This would also be a useful feature for those with older synths that pack multiple parameters into one byte.
I think you are stuck with just 32 encoders if you want a stand alone BC with the faders keeping their value.
Again, your patch swapping - CC updating could be done with the 'man in the middle' computer (or micro-controller) by making the computer put out all the common CC values when a BC patch change occurs.
There are a lot of cheap, small and powerful controllers (eg Arduino or Raspberry Pi) if you are able to program.
It would be a fairly simple take to get any 8bit micro-controller to track the 8 CC values from the faders and when it received a patch change message to output those values.
This is what I would do , but perhaps that is due to me being cheap and having a drawer full of 8 bit controllers.
I'm not a OSX person, but Junxion could work if it will let you use a Midi command to 'page' in your faders as new CC types.
Al the best
Royce