On the neutral coop problem, I seem to recall allied players from different races could do limited neutral coop (like first mission only) before it stopped working. Maybe that was the same for same-race players, but my recollection is allies were better than species-mates.
Regarding test servers, I'm asking Castrin now about possibly running NW's scripts AND the Taldren ones under the test server kit so we can run through the entire list and chart the DV effects from each mission with as many different variables as possible. This would take a lot of time and coordination. One thing I'm wondering about is if we could create a web-based reporting tool to track test results. To take best advantage of the testing, the DV change should be set at 1 point per mission, with a wide range of starting DVs and different empire/cartel hex ownership overlaps. Politics would have to be closely monitored, of course.