How much more energy is required to operate the pump as compared to conventional systems?
LOTS more! The 06 takes considerable effort, relatively little leverage on the commercial model, at the rate of 40 strokes per minute, to produce a bit over a liter per hour. Do the math, that equals 2400 strokes to desalinate about a quart of water. Believe me when I say this is not easy or much fun. It's better than dying of dehydration, but do it for long and you will lose plenty of weight. If you aren't in particularly good shape and are by yourself, you will run out of steam in less than an hour. Anything much less than 40 strokes/minute doesn't work and anytime you stop, you have to flush the system again. The 35 is much better, but also much bigger and more expensive, weighing in at 7 lbs. Still have to keep that stroke up, but the longer pump arm makes it a little bit easier. It produces water at the rate of about 1.5 gallons per hour.
Would it then be fair to say, cost aside and/or energy input requirements, the Katadyn PUR Survivor 06 and 35 Reverse Osmosis Manual Desalinator Pumps theoretically would be the gold standard or the best universal system to have even if not around a marine environment on a regular basis?
If energy input isn't part of the equation, theoretically yes, but you also have to ensure the water is pretty clean to begin with, as in tap water clean, because the membrane will clog very quickly otherwise. They make electrically operated versions and many other companies also make electrically operated marine RO desalinators. They aren't found in other environments because there's lots more economical and efficient ways to purify dirty or contaminated water via conventional filters and/or chemical treatments. There are no other compact or efficient ways to desalinate water.