I don't think you are missing anything... you seem to have considered all the choices.
I realize that I was mistaken about what will happen in the specific circumstance you are working with.
I guess I never export a mono track and always export stereo tracks, simply by circumstance, not by preference, and so I thought 0dB Center Balance control would eliminate the issue.
It will not, but in all other respects it seems to me that 0dB Center Balance control is the most predictable and offers the least unexpected consequences so that is why I prefer to use it.
best regards,
mike