My feelings are this, as the Zoners are predominantly supposed to be independent of the houses and mainly trade based this is an excellent suggestion.
The name of the "cargo" in question should simply be Zoner workers, I think of the Zoners as traders and manual workers mainly, I see them in pretty much the same light as oil rig workers or engineers, out in space on distant installations tinkering with wrenches (not wenches Mal before you start!), andgetting their hands dirty.
As Gran is the only homeworld we have that would be any Zoners ultimate holiday destination and the place they are most likely go for a break so that would naturally attract the highest return, and likewise the farthest Zoner bases would have the lowest price for this commodity, i.e Freeport 6, ames, FP10.
N.B. As Zoners are predominantly anti-house, any workers would be unlikely to step aboard any ship that isn't at least a freelancer or ally's therefore only people with those id's should be allowed to transport them.