None of which need matter in the context of THIS game.
That's true, but if you're starting over why not start over?
The Zhurphani are really obscure, as already noted, so the write-up we have is not particularly binding.
"Not being binding" is what I've been suggesting. Thanks to T5, san*klass could populate his "proto"-Regina subsector with his own NILs in locations he's chosen. There's no real need to use the Zhurphs, Urtsy, or any others.
It also notes that the Zhurph are not actually native, which is an obvious "secret" for PCs and/or the political types to discover and react to.
Good point. While that's not any secret in the 12th Century IE, it should already be suspected in the 1st Century IE. Simple taxonomic observations will suggest that the Zhurphs (and possible some flora and fauna) aren't native to Yori and "DNA" tests easily will confirm it. Attempts to find what's left of the STL ship could be a nice adventure.
In Milieu 100, there is no overpopulated Roup, no dagger at Efate, no insular dictatorship at Algine. Not even the Octagon Society, which is still two centuries away. Beck's World is still identified as the Frisini System.
I thought Algine was the result of two "failed" colonies both, one Vilani/jump, one Solomani/STL, both about 1000 years apart, and with the resulting culture(s) very xenophobic thanks to a period of Vargr raiding. Anyway, the IISS will have an interdiction in place by the 2nd Century.
Prior to T5, NILs tended to be placed on worlds which weren't attractive to humans. After T5, the opposite is true. The higher the system population, the better chance NILs, either Native or Exotic, are present. Some results like the Urtsy still occur, but NILs will more often show up where more humans exist.
With san*klass linking population levels to "shirtsleeve" environments, systems like Efate, Heya, or Alell are going to have NILs while OTU NILs like those on Yori or Yurst won't exist.