This only works if you ignore all but one 3D axis. Either connector depends on being specifically aligned along two other axes, whether or not they're rotationally symmetrical about the third. People are overthinking this stuff.
Depends on the application. Some come across, some require re-entering activation codes, some require you to de-activate before you do the upgrade, then re-activate after it's done. Seems to be as much results of individual company's policy as anything else.
Think back on digital camera image quality around 2004. High quality output was very expensive, affordable not nearly so much. The original images shown in the article were likely shot on film, either C41 process, or fast black and white, like Tri-X or Tmax-400.
Sorry, OS X abandoned the Display PostScript approach that NeXT used right from the beginning in favor of their own version of PDF-based rendering. IIRC, it was initially done because they couldn't come to an agreement with Adobe on using Display PostScript, but OS X never shipped with it.