2012 rPro or 2013 Air?

Final cut pro (video editing), logic pro (music editing), aperture (photo editing), and the various adobe suites are generally meant to be optimized for the macbook pro, although the air can handle them it will do so at a lower resolution and with slower abilities due to the lack of cpu power. The air is essentially the modern day macbook, if your macbook was good enough that it handled all of your tasks, the air is perfectly fine.

2013 Air unless you need it for heavy duty apps as mentioned by previous poster.

Otherwise, 2013 MBA is better for day-to-day use (longer battery life, faster SSD, etc.).

None. The i7 MBA may well outperform the rMBP you mention.

If you're comparing 13" models, the only notable difference between the two models is the screen. In terms of heavy cpu lifting/gpu stuff, both models will not be sufficient if you're using it professionally (or you're a "power" consumer or something). If you like the screen and don't mind paying the premium, just get the rMBP. If you want the battery life, get the Air. If you want the power but still want portability, you'll have to get a 15" rMBP.